Sync FSX with FSFS.  Block 'svnfsfs stats' changes:
r1639319, r1639322, r1639335, r1639348, r1639352, r1639355, r1639426,
r1639430, r1639436, r1639440 and r1639549

* subversion/libsvn_fs_x
  (): Update mergeinfo.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1645580 13f79535-47bb-0310-9956-ffa450edef68