Fix the performance regression of packed vs. non-packed repos in 1.9 if
revprop caching has been disabled.

The 1.9 default "compress packed revprops" added about 1ms CPU delay
before the requested revision properties can be accessed.  With revprop
caching enabled, this easily pays off by not having to read multiple
revprop pack files per shard (10ms each for HDD-backed repos).  Without
revprop caching, disk-cached non-compressed revprops will be faster.

* subversion/libsvn_fs_fs/fs_fs.c
  (read_config): Default to not compressing packed revprops.
  (write_config): Update FSFS config template to reflect the new /
                  restored default.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1604414 13f79535-47bb-0310-9956-ffa450edef68