Reinstate (void) casts removed in r1464228, r1464060 and r1464058 while
keeping all the other code changes in those revisions.

* subversion/libsvn_delta/path_driver.c
  (pop_stack): Add cast.

* subversion/libsvn_ra_serf/util.c
  (svn_ra_serf__conn_closed, xml_parser_cleanup,
   svn_ra_serf__process_pending, svn_ra_serf__handle_xml_parser,
   svn_ra_serf__credentials_callback, svn_ra_serf__request_create,
   expat_start, expat_end, expat_cdata, expat_response_handler): Add cast.

* subversion/libsvn_repos/hooks.c
  (parse_hooks_env_section, svn_repos__parse_hooks_env): Add cast.

* subversion/libsvn_subr/config.c
  (svn_config_find_group): Add cast.

* subversion/mod_dav_svn/liveprops.c
  (is_writable, dav_svn__insert_all_liveprops): Add cast.

* subversion/mod_dav_svn/lock.c
  (unescape_xml): Add cast.

* subversion/mod_dav_svn/mod_dav_svn.c
  (merge_xml_in_filter): Add cast.

* subversion/mod_dav_svn/util.c
  (dav_svn__final_flush_or_error): Add cast.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1466162 13f79535-47bb-0310-9956-ffa450edef68