Fix the problem: Two people from 2 different working copies at revision rX  trying to do a merge of rY and rZ independently from /branch/b1 to /trunk.  Assume the first person commits(merge of rY), when second guy tries to do the commit(merge of rZ) he would get a out of date error. So second guy would do 'svn up'. svn up does not merge the 'svn:mergeinfo' correctly It just keeps rZ.
Fix the problem: Two people from 2 different working copies at revision rX 
trying to do a merge of rY and rZ independently from /branch/b1 to /trunk. 
Assume the first person commits(merge of rY), when second guy tries to
do the commit(merge of rZ) he would get a out of date error. So second
guy would do 'svn up'. svn up does not merge the 'svn:mergeinfo' correctly
It just keeps rZ.

* subversion/libsvn_wc/props.c
  (svn_wc__merge_props): Record the merged svn:mergeinfo on the target.
   
Found by: Piet-Hein Peeters
Reviewed by: dlr


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@865720 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion