Update a deprecated function call, and in the process fix a segfault or two.
Update a deprecated function call, and in the process fix a segfault or two.

* subversion/libsvn_repos/rev_hunt.c
  (get_merged_mergeinfo): Use svn_mergeinfo_diff2() instead of
    svn_megeinfo_diff().


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1185650 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion