Enhance the regression test added by Bert in r1603497 to check both revs.

* subversion/tests/cmdline/lock_tests.py
  (lock_commit_bump): Add explicit check for both 'Revision' and
    'Last Changed Revision' not being bumped, as the implicit check
    performed after the commit only checks the first one.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1603750 13f79535-47bb-0310-9956-ffa450edef68