Follow-up to r1643139: Fix pool cleanup loophole.
Follow-up to r1643139: Fix pool cleanup loophole.

* subversion/libsvn_fs_fs/caching.c
  (remove_txn_cache_txn,
   remove_txn_cache_fs): Since we always register both cleanups, we must
                         always cleanup the respective other - even if the
                         cache object itself has already been removed. 

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1643233 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion