convert: raise Abort instead of NoRepo when CVS pserver auth fails.
At this point we know the source is CVS, so we should not go through
the rest of the converters.
to build a new macosx binary package:
install macpython from http://www.python.org/download/mac
install py2app from http://pythonmac.org/packages/
make sure /usr/local/bin is in your path
run bdist_mpkg in top-level hg directory
find packaged stuff in dist directory