[Forwardport] Fix bug with __all__ creation in partner app

A simple typo lead to star imports not working as expected. As it's
easily worked around, we won't issue a release right away.

Closes #1553.

(cherry picked from commit 80babf2c19ff6d3934623dde222b66adb69c71a0)

Conflicts:
	docs/source/releases/index.rst