Move svnfsfs from our tools section to subversion main.

* tools/server-side/svnfsfs: Moved to ...
* subversion/svnfsfs: ... this.

* subversion/svnfsfs/dump-index-cmd.c,
  subversion/svnfsfs/load-index-cmd.c,
  subversion/svnfsfs/stats-cmd.c: Update relative include paths.

* build.conf
  (svnfsfs): Point to the new location.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1618848 13f79535-47bb-0310-9956-ffa450edef68