A recent change to split sql_create_models() passed the wrong model to

a call to sql_for_pending_references(), which resulted in some bad SQL

that would break on MySQL. We were executing SQL for creating pending

references on the model being created when we meant to do that for

models being referenced by the model (via a ForeignKey or similar

fields). This change fixes that variable, fixing all tests.

All unit tests pass for all databases.