Prevent forced reloading of doctest which was breaking lots of tests.
Prevent forced reloading of doctest which was breaking lots of tests.

This was the very hard to track source of many test problems.  The
doctest_reload() function name wasn't changed, but it doesn't actually do
reload(doctest) anymore.  This is sufficient to clean a large number of test
errors in one shot.

ipython/ipython,ipython/ipython