Sync'ing FSX with FSFS:
Merge r1512301,1540044,1540057,1589235,1589284 from /subversion/libsvn_fs_fs
into subversion/libsvn_fs_x.  Various conflicts had to be resolved.

This ports the hotcopy and config file changes in one go as they are related.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1595104 13f79535-47bb-0310-9956-ffa450edef68