On the fsfs-format7 branch: Enable optional format6 features
by default now.

* subversion/libsvn_fs_fs/fs_fs.c
  (read_config): deltify dirs and props by default; also compress revprops
  (write_config): reflect the new defaults


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1438406 13f79535-47bb-0310-9956-ffa450edef68