Fix issue #4366 ("client SEGFAULTs diffing a repos rev in which an
empty file was added").

* subversion/libsvn_client/repos_diff.c
  (apply_textdelta): Pass TRUE for the open_on_close parameter of
    calls to svn_stream_lazyopen_create().

* subversion/tests/cmdline/diff_tests.py
  (diff_repos_empty_file_addition): Remove @XFail() decorator.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1482970 13f79535-47bb-0310-9956-ffa450edef68