Correct an accidental lack of checking in the regression tests. The expected

Correct an accidental lack of checking in the regression tests.  The expected
stderr was often specified as "None" (meaning ignore it) where "[]" (meaning
no output) was intended, so the tests were not as strict as they should be.

Prevent this particular case from happening again by disallowing "None" as the
"expected_stderr" argument of the two functions involved, since its meaning
was too confusing and that facility doesn't appear to be needed.  If it is
needed in future, it should be handled by something similar to "SVNAnyOutput".

* subversion/tests/clients/cmdline/svntest/actions.py
  (run_and_verify_svnversion, run_and_verify_svn): Raise an exception if
    "expected_stderr" is "None".

* subversion/tests/clients/cmdline/basic_tests.py
* subversion/tests/clients/cmdline/cat_tests.py
* subversion/tests/clients/cmdline/commit_tests.py
* subversion/tests/clients/cmdline/copy_tests.py
* subversion/tests/clients/cmdline/diff_tests.py
* subversion/tests/clients/cmdline/history_tests.py
* subversion/tests/clients/cmdline/import_tests.py
* subversion/tests/clients/cmdline/lock_tests.py
* subversion/tests/clients/cmdline/merge_tests.py
* subversion/tests/clients/cmdline/prop_tests.py
* subversion/tests/clients/cmdline/revert_tests.py
* subversion/tests/clients/cmdline/svnversion_tests.py
* subversion/tests/clients/cmdline/trans_tests.py
* subversion/tests/clients/cmdline/update_tests.py
* subversion/tests/clients/cmdline/utf8_tests.py
  Pass "[]" instead of "None" for "expected_stderr" in calls to
    run_and_verify_svnversion() and run_and_verify_svn().

git-svn-id: http://svn.apache.org/repos/asf/subversion/trunk/subversion/tests/clients/cmdline@856154 13f79535-47bb-0310-9956-ffa450edef68