Corrected "how to use module" comment in svntest/main.py.
Corrected "how to use module" comment in svntest/main.py.

* subversion/tests/cmdline/svntest/main.py: Corrected "how to use
  module" comment.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion