On the log-addressing branch:  Fix rev / pack file access when
the FS got packed since the last access.

* subversion/libsvn_fs_fs/rev_file.c
  (open_pack_or_rev_file): once we managed to open a pack / rev file,
                           update the "is-packed" flag as used for this file

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/log-addressing@1535729 13f79535-47bb-0310-9956-ffa450edef68