hgext/__init__.py

revlog: tweak wording and logic for flags validation

First, the logic around the if..elif..elif was subtly wrong
and sub-optimal because all branches would be tested as long as
the revlog was valid. This patch changes things so it behaves like
a switch statement over the revlog version.

While I was here, I also tweaked error strings to make them
consistent and to read better.

from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)