Helper code for reproducing issue #4274 (serf client hangs when server crashes).

* subversion/libsvn_repos/repos.c (get_repos): When SVN_DEBUG is defined,
   if the file $REPO_PATH/conf/debug-abort exists, crash after opening
   the repository and filesystem.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1431757 13f79535-47bb-0310-9956-ffa450edef68