Add a project setting to disable automatic Django Evolution behavior.

Review Request #7585 — Created Aug. 13, 2015 and submitted — Latest diff uploaded

Django Evolution

When projects begin migrating to Django migrations and away from Django
Evolution, we'll want to ensure that Django Evolution doesn't attempt to
make any further changes to the database.

A new settings.DJANGO_EVOLUTION_ENABLED flag (defaulting to True) is
now supported. When turned off, Django Evolution won't listen for syncdb
anymore, and the evolve command will exit with an error.

Set DJANGO_EVOLUTION_ENABLED = False and ran syncdb and evolve.

syncdb didn't try to invoke the Django Evolution logic, and evolve gave
me an error saying that evolutions were disabled for the project.