[1.7.x] Fixed #23699 -- Prevented flush from loading initial data for apps with migrations.

Backport of dd1ea70779 from master.

tests/fixtures_migration/tests.py

@@ -0,0 +1,31 @@
+from django.test import TestCase
+from django.core import management
+
+from .models import Book
+
+
+class TestNoInitialDataLoading(TestCase):
+    """
+    Apps with migrations should ignore initial data. This test can be removed
+    in Django 1.9 when migrations become required and initial data is no longer
+    supported.
+    """
+    available_apps = ['django.contrib.auth', 'django.contrib.contenttypes', 'fixtures_migration']
+
+    def test_migrate(self):
+        self.assertQuerysetEqual(Book.objects.all(), [])
+        management.call_command(
+            'migrate',
+            verbosity=0,
+        )
+        self.assertQuerysetEqual(Book.objects.all(), [])
+
+    def test_flush(self):
+        self.assertQuerysetEqual(Book.objects.all(), [])
+        management.call_command(
+            'flush',
+            verbosity=0,
+            interactive=False,
+            load_initial_data=False
+        )
+        self.assertQuerysetEqual(Book.objects.all(), [])