This function is called now before flower.start() is called to make sure we have a working broker and starting Flower will set it up correctly.
This is a first attempt at solving the issue of Flower booting up in a broken state.

There can be a race condition from the moment we checked the condition to the moment we call flower.start() although unlikely.
I will ponder on that...

As of celery 5 the command line invocation no longer supports specifying celery args after flower command.
Also add depends_on for flower.

We no longer have `flower` as a separate command and this entrypoint was incorrect.
We also need to be able to fully override the arguments for celery and flower via command line arguments when using the image.

We should start adding those in this file as they are merged - I had hard time remembering what I have done over the last few months.

# Conflicts:
#	CHANGES

…into investigate-no-comms-in-docker