Revision 1834612

On the '1.10.x-issue4758' branch: Fix SVN-4758 "Unable to shelve changes
when using custom diff-cmd".

* subversion/libsvn_client/shelve.c
  (shelf_write_patch): Ignore any config file while executing the diff, so
    as to use the internal diff code.
 
* subversion/tests/cmdline/shelve_tests.py
  (shelve_unshelve_verify,
   shelve_unshelve): Allow specifying global options.
  (shelve_ignores_external_diff): New test.
  (test_list): Run it.