Fix yet another global pool destruction ordering bug in the bdb cache.
Fix yet another global pool destruction ordering bug in the bdb cache.

* subversion/libsvn_fs_base/bdb/env.c
  (svn_fs_bdb__close): Don't bother removing entries from the bdb cache
   if bdb_cache_lock is NULL, since that indicates that we're already in
   global pool destruction time and the bdb cache pool has already been
   destroyed.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@860791 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion