changes: Fix file without ticket number

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

changes/bsd_libc

-  o Minor bugfixes (compilation):
+  o Minor feature (compilation):
     - Fix returning something other than "Unknown N/A" as libc version if we
       build tor on an O.S. like DragonFlyBSD, FreeBSD, OpenBSD or NetBSD.