[rfc] time to remove LANG=C run from make check

[Martin Pool]

I think it's time to bite the bullet and close bug 386180 by not
running the test suite a second time with LANG=C from 'make check'.
This would cut in half (almost) the pqm latency.  Now that we have a
working buildbot and vila's reporting the results in the release
process, we can do a test for the ascii locale (or any other locale)
asynchronously with merges.

If it turns out we get more encoding-related bugs we may roll it back.

Eventually it would be nice to synchronously but in parallel test
across all platforms and environments.

If no one screams I'll land this to trunk (but not 2.0 of course) in a
couple of days.

-- 
Martin <http://launchpad.net/~mbp/>