Fix for pool cleanup.
Fix for pool cleanup.

Suggested by: Sander Striker <striker@apache.org>

* libsvn_subr/svn_error.c (allocator_reset_mutex): New function.
(svn_pool_create, svn_pool_clear): Register it as a pool cleanup if a
mutex has been registered in the pool allocator.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion