Commit 2ae740dd49 probably inadvertently
changed to iterate over a set of "create_app", "make_app" to discover
application factory functions. As sets don't guarantee order,
differences in the implementation of the type can make it
non-deterministic which factory function is used if a project implements
both. Revert to using a tuple.
Signed-off-by: Nils Philippsen <nils@redhat.com>
cf3089a8f8