Sync'ing FSX with FSFS:
Merge r1525419,1525484,1526014 and 1532893 from /subversion/libsvn_fs_fs
into subversion/libsvn_fs_x.  The first 3 are no-ops has the respective
code had been ported earlier.

This ports the move-handling patches.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1595600 13f79535-47bb-0310-9956-ffa450edef68