Summary: This allows us to use fastmanifest as a directory to drop in the python module.
Test Plan: compiles, passes existing tests.
Reviewers: lcharignon
Reviewed By: lcharignon
Subscribers: mitrandir, mjpieters
Differential Revision: https://phabricator.intern.facebook.com/D3351021
Signature: t1:3351021:1464284417:6cbcde514ab1fd7b5caa6c83cb5577f3502dbc58