Followup to r1515343: fully fix svnsync revision number formatting. 

* subversion/svnsync/svnsync.c:
  (replay_rev_finished): Prefix both revisions in output with r.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1515721 13f79535-47bb-0310-9956-ffa450edef68