Fix a portion of issue #3764 ("Replace + propset of locked file fails over DAV"), specifically the part that involves explicitly replaced files (as opposed to files re-added under replaced directories).
Fix a portion of issue #3764 ("Replace + propset of locked file fails
over DAV"), specifically the part that involves explicitly replaced
files (as opposed to files re-added under replaced directories).

* subversion/libsvn_ra_serf/commit.c
  (maybe_set_lock_token_header): New helper function.
  (setup_proppatch_headers, setup_put_headers): Now use
    maybe_set_lock_token_header() to handle the decision and effort of
    adding the lock token If: precondition header to the request.

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