Fixed #14300 -- Fixed initial SQL location if models is a package.

Thanks al_the_x for the report and fheinz for the draft patch.

tests/fixtures_model_package/models/sql/book.sql

@@ -0,0 +1,2 @@
+-- Deprecated search path for custom SQL -- remove in Django 1.9
+INSERT INTO fixtures_model_package_book (name) VALUES ('My Deprecated Book');