On the log-addressing branch: fix undefined symbol on link.

* build.conf
  (fs-test): Link to libsvn_fs_util for svn_fs__compatible_version.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/log-addressing@1532410 13f79535-47bb-0310-9956-ffa450edef68