Fix a pool usage issue: svn_cache__get_partial() may be called many times in a row. Thus, the internal pool used to construct keys should be cleared in this function as well from time to time.
Fix a pool usage issue: svn_cache__get_partial() may be called many
times in a row. Thus, the internal pool used to construct keys should
be cleared in this function as well from time to time.

* subversion/libsvn_subr/cache-membuffer.c
  (svn_membuffer_cache_get_partial): regularly clear the internal scratch pool

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1127709 13f79535-47bb-0310-9956-ffa450edef68

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