Follow-up to r1514318: fix getopt_tests failures.

* subversion/tests/cmdline/getopt_tests.py
  (load_expected_output): Filter out 'using serf x.x.x' from actual output.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1514356 13f79535-47bb-0310-9956-ffa450edef68