Also improve the unittest to make sure it catches the right error.

This will fail currently since the bug is not fixed yet.

This avoids a double-free when a pointer already freed with
tor_free(config_line) is freed again in the cleanup-and-exit code.

Fixes bug 23155.

This is partial revert on 22286.

Also, tweak some log messages to be distinct.

Fixes bug 23139; bugfix on 0.3.1.1-alpha.

Patch from Vort; fixes bug 23081; bugfix on fd992dee in
0.2.1.16-rc when set_main_thread() was introduced.

See the changes file for a list of all the symptoms this bug has
been causing when running Tor as a Windows Service.

"ours" merge to avoid version bump.

"Ours merge" to avoid version bump.

One log statement was a warning and has been forgotten. It is triggered for a
successful attempt at introducting from a client.

It has been reported here:
https://lists.torproject.org/pipermail/tor-relays/2017-August/012689.html



Three other log_warn() statement changed to protocol warning because they are
errors that basically can come from the network and thus triggered by anyone.

Fixes #23078.

Signed-off-by: David Goulet <dgoulet@torproject.org>