Create r0 contents only after initializing the config data, thus
removing the need to temporarily initialize parts of the FFD.

* subversion/libsvn_fs_fs/fs_fs.c
  (write_revision_zero): Remove FFD init bits. 
  (svn_fs_fs__create): Write r0 only after initializing all in-memory data.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1606744 13f79535-47bb-0310-9956-ffa450edef68