Removed obsolete references to django.core.urlresolvers. Added the
newly required on_delete parameters to foreign key relationships in
models.py and in all migrations.
(Amber Elliot's 2d526f9b0d served as a
reference for these changes).
Signed-off-by: Paul Eggleton <paul.eggleton@linux.microsoft.com>
RecipeUpstreamHistory was not linked to the layer it was produced from,
which meant that it wasn't easy to query for a different maintenance
plan (i.e. a different layer) and thus the maintenance plan selection
on the recipe list didn't really work. Add a link field, populate it in
a migration and then make it required.
We had added a link earlier from RecipeMaintainerHistory to LayerBranch
but it was optional; for the same reasons we now populate it and make it
required.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>