Rename dummy instance creation methods

The dummy instance creation methods do not need "Dummy" in their
name, as they are all in the Dummy class.

Issue: HIC-286
Change-Id: I688eaf0d67f5357dd386a701f958dc57a889a6c6
diff --git a/crashreports/tests/test_models.py b/crashreports/tests/test_models.py
index d12189d..d14155f 100644
--- a/crashreports/tests/test_models.py
+++ b/crashreports/tests/test_models.py
@@ -21,14 +21,14 @@
 
     def _assert_duplicate_entries_can_not_be_created(self, object_type):
         # Create a user, device and a report
-        user = Dummy.create_dummy_user()
-        device = Dummy.create_dummy_device(user)
-        Dummy.create_dummy_report(object_type, device)
+        user = Dummy.create_user()
+        device = Dummy.create_device(user)
+        Dummy.create_report(object_type, device)
 
         # Assert creating a duplicate report fails
         logger = logging.getLogger("crashreports")
         with self.assertLogs(logger, "DEBUG") as logging_watcher:
-            report = Dummy.create_dummy_report(object_type, device)
+            report = Dummy.create_report(object_type, device)
         self.assertEqual(
             logging_watcher.output,
             [