Fix last failing tests with postgres

Author: vrigal

tests/conftest.py

@@ -705,7 +705,7 @@ def test_perf_data(test_perf_signature, eleven_jobs_stored):
     # for making things easier, ids for jobs
     # and push should be the same;
     # also, we only need a subset of jobs
-    perf_jobs = th_models.Job.objects.filter(pk__in=range(7, 11)).order_by('push__time', 'id').all()
+    perf_jobs = th_models.Job.objects.filter(pk__in=range(7, 11)).order_by('id').all()
 
     for index, job in enumerate(perf_jobs, start=1):
         job.push_id = index

tests/model/cycle_data/test_perfherder_cycling.py

@@ -838,7 +838,7 @@ def test_deleting_performance_data_cascades_to_perf_datum_replicate(test_perf_da
         cursor = connection.cursor()
         cursor.execute(
             '''
-            DELETE FROM `performance_datum`
+            DELETE FROM performance_datum
             WHERE id = %s
             ''',
             [perf_datum.id],