Revision 1884617

Merge r1880192 from trunk:

 * r1880192
   Fix issue #4862 "Merge: the resulting mergeinfo is non-deterministic".
   Justification:
     Non-deterministic merge result is bad.
   Depends:
     r1878997, r1879192, r1879474, r1879959 (Fix issue #4859)
   Votes:
     +1: julianfoad, hartmannathan, jcorvel