Remove unneeded error handling.

* subversion/libsvn_fs_fs/fs_fs.c
  (svn_fs_fs__info_format): Remove handling error cases that svn_fs_open()
    should have taken care of.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1465154 13f79535-47bb-0310-9956-ffa450edef68