maint-0.2.9: remove changes files that are merged in 0.2.9 releases

Many of these files cause check-changes to fail, which will be a
long-term problem as we continue to support 0.2.9.

changes/19974

-  o Minor bugfixes (unit tests):
-    - Fix tolerances in unit tests for monotonic time comparisons between
-      nanoseconds and microseconds. Previously, we accepted a 10 us
-      difference only, which is not realistic on every platform's
-      clock_gettime(). Fixes bug 19974; bugfix on 0.2.9.1-alpha.

changes/20460

-  o Minor bugfixes (testing):
-    - Use ECDHE ciphers instead of ECDH in tortls tests. LibreSSL has
-      removed the ECDH ciphers which caused the tests to fail on
-      platforms which use it. Fixes bug 20460; bugfix on 0.2.8.1-alpha.

changes/20492

-  o Minor bugfix (build):
-    - The current Git revision when building from a local repository is now
-      detected correctly when using git worktrees.  Fixes bug 20492; bugfix on
-      0.2.3.9-alpha.

changes/21359

-
-  o Minor features (portability, compilationc)
-    - Support building with recent LibreSSL code that uses opaque
-      structures. Closes ticket 21359.
-    - Autoconf now check to determine if OpenSSL
-      structures are opaque, instead of explicitly checking for
-      OpenSSL version numbers. 
-      Part of ticket 21359.

changes/bastet_v6

-  o Minor features (directory authority):
-    - Add an IPv6 address for the "bastet" directory authority.
-      Closes ticket 24394.
-

changes/bug15582

-  o Minor bugfixes (compilation):
-    - Avoid compiler warnings in the unit tests for running tor_sscanf()
-      with wide string outputs. Fixes bug 15582; bugfix on 0.2.6.2-alpha.
-

changes/bug18100

-  o Major bugfixes (linux TPROXY support):
-    - Fix a typo that had prevented TPROXY-based transparent proxying from
-      working under Linux. Fixes bug 18100; bugfix on 0.2.6.3-alpha.
-      Patch from "d4fq0fQAgoJ".
-

changes/bug18329-minimal

-  o Minor features (bridge):
-    - Bridges now include notice in their descriptors that they are bridges,
-      and notice of their distribution status, based on their publication
-      settings.  Implements ticket 18329.  For more fine-grained control of
-      how a bridge is distributed, upgrade to 0.3.2.x or later.
-

changes/bug19025

-  o Major bugfixes (DNS):
-    - Fix a bug that prevented exit nodes from caching DNS records for more
-      than 60 seconds.
-      Fixes bug 19025; bugfix on 0.2.4.7-alpha.

changes/bug19869

-  o Minor bugfixes (DNSPort):
-    - On DNSPort, stop logging a BUG warning on a failed hostname lookup.
-      Fixes bug 19869; bugfix on 0.2.9.1-alpha.
-

changes/bug19926_029_info

-  o Minor bugfixes (logging):
-    - Downgrade a harmless log message about the pending_entry_connections
-      list from "warn" to "info". Mitigates bug 19926.

changes/bug19960

-  o Minor bugfixes (netbsd, unit tests):
-    - Stop expecting NetBSD unit tests to report success for ipfw;
-      on NetBSD, it's only pf that's supported.
-      Part of a fix for bug 19960; bugfix on 0.2.9.5-alpha.

changes/bug19968

-  o Minor bugfixes (relay):
-    - Do not try to parallelize workers more than 16x without the
-      user explicitly configuring us to do so, even if we do detect more than
-      16 CPU cores. Fixes bug 19968; bugfix on
-      0.2.3.1-alpha.
-
-
-  o Minor bugfixes (testing):
-    - Avoid a unit test failure on systems with over 16 detectable
-      CPU cores. Fixes bug 19968; bugfix on
-      0.2.3.1-alpha.

changes/bug19969

-  o Major bugfixes (client performance):
-    - Clients now respond to new application stream requests when
-      they arrive, rather than waiting up to one second before starting
-      to handle them. Fixes part of bug 19969; bugfix on 0.2.8.1-alpha.
-
-  o Major bugfixes (clients on flaky network connections):
-    - When Tor leaves standby because of a new application request, open
-      circuits as needed to serve that request. Previously, we would
-      potentially wait a very long time. Fixes part of bug 19969; bugfix
-      on 0.2.8.1-alpha.

changes/bug20059

-  o Minor bugfixes (relay):
-    - Avoid a double-marked-circuit warning that can happen when we receive
-      DESTROY cells under heavy load. Fixes bug 20059; bugfix on 0.1.0.1-rc.

changes/bug20085

-  o Documentation:
-    - Correct the minimum bandwidth value in torrc.sample, and queue a
-      corresponding change for torrc.minimal. Closes ticket 20085.
-

changes/bug20235

-  o Minor features (compatibility):
-    - Work around a bug in the OSX 10.12 SDK that would prevent us
-      from successfully targetting earlier versions of OSX.
-      Resolves ticket 20235.

changes/bug20247

-  o Minor bugfixes (linux seccomp2 sandbox):
-    - Avoid a sandbox failure when trying to re-bind to a socket and mark
-      it as IPv6-only. Fixes bug 20247; bugfix on 0.2.5.1-alpha.
-

changes/bug20306_029

-  o Minor bugfixes (fascistfirewall):
-    - Avoid spurious warnings when ReachableAddresses or FascistFirewall
-      is set. Fixes bug 20306; bugfix on 0.2.8.2-alpha.
-

changes/bug20307

-  o Minor bugfixes (circuit, hidden service)
-    - When closing a circuit, the reason for doing so was assigned from an int
-      value to a uint16_t which is quite a problem for negative values that are
-      our internal reasons (ex: END_CIRC_REASON_IP_NOW_REDUNDANT). On the HS
-      side, this was causing introduction points to be flagged as unusable
-      because the reason wasn't the right one due to the bad conversion.
-      Partially fixes bug 21056 and fixes bug 20307; Bugfix on 0.2.8.1-alpha.