Update a few more deprecated function calls.
Update a few more deprecated function calls.

* subversion/libsvn_client/merge.c
  (filter_self_referential_mergeinfo, process_children_with_new_mergeinfo,
   record_mergeinfo_for_added_subtrees, find_unmerged_mergeinfo):
    Use svn_mergeinfo_merge2().

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion