Allow import redirections

When we move modules out of namespace packages we set up redirects to
import the new module under the old name. Python's import machinery
doesn't detect those things as modules, and the names don't show up in
sys.modules. However, if we look at what we actually got when we did the
import we can see that it is a module.

Change-Id: I4b42d081965b6d898b178cbe9232b47cfed17d8a
(cherry picked from commit dd8b4d63331d435ff79e6f4a50b7f6cee384f9ba)