ra_serf: Accept a 204 as a valid response to a COPY per RFC 2518 / 8.8.5.
ra_serf: Accept a 204 as a valid response to a COPY per RFC 2518 / 8.8.5.

Passes switch test #8 (relocate with deleted, missing and copied entries).

* subversion/libsvn_ra_serf/update.c
  (close_file): Accept 201 and 204 as valid response.

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