Speed up revprop access in svn_repos_dump_fs4() by using the latest FS API.
Speed up revprop access in svn_repos_dump_fs4() by using the latest FS API.

* subversion/libsvn_repos/dump.c
  (write_revision_record): Read revprops from the FS cache if we can. 
  (svn_repos_dump_fs4): Refresh the revprops only once, at the start of the
                        operation.  This is the only public function that
                        calls the above.  Therefore, we still fulfill the
                        visibility guarantees for revprop changes.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1708000 13f79535-47bb-0310-9956-ffa450edef68

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