Sync FSX with FSFS.  Block revisions related to revprop caching removal:
r1639358 and r1639419.

* subversion/libsvn_fs_x
  (): Update mergeinfo.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1645581 13f79535-47bb-0310-9956-ffa450edef68