Duct tape a test that broke the build.

* subversion/tests/cmdline/cat_tests.py
  (cat_skip_uncattable): Hack in the logic that run_and_verify_svn2() already
    does.  For some reason this test doesn't use it :(

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1469886 13f79535-47bb-0310-9956-ffa450edef68