Revert "Use require_package('python-mwclient') to solve a duplicate package def"

And fix another way, since require_package doesn't seem to work...

This reverts commit c4291d0f62205a890927ec15f6f9c43a3d68b97b.

Change-Id: I26df34abe8f707ba121c86ab44fcf3fa00b94e45