Simplify a bit of merge code.
Simplify a bit of merge code.

* subversion/libsvn_client/merge.c
  (filter_merged_revisions): Take the target mergeinfo in the form of a
    rangelist rather than a mergeinfo structure that's assumed to contain
    just that one rangelist.
  (calculate_remaining_ranges): Calculate the portion of the target
    mergeinfo that refers to the source as a rangelist rather than a
    mergeinfo structure that contains just that one rangelist.

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