bsn_flow_checksum: add TableChecksumIds test

We had a bug in Indigo where the table ID wasn't being populated in the table
checksum stats reply. This test would have caught it.
diff --git a/tests-1.3/bsn_flow_checksum.py b/tests-1.3/bsn_flow_checksum.py
index 11bbedc..26f40e9 100644
--- a/tests-1.3/bsn_flow_checksum.py
+++ b/tests-1.3/bsn_flow_checksum.py
@@ -250,3 +250,12 @@
         do_barrier(self.controller)
         error, _ = self.controller.poll(ofp.OFPT_ERROR)
         self.assertIsInstance(error, ofp.message.error_msg)
+
+class TableChecksumIds(FlowChecksumBase):
+    """
+    Check that each table is represented in the table checksum stats reply
+    """
+    def runTest(self):
+        table_checksum_stats_ids = [x.table_id for x in get_stats(self, ofp.message.bsn_table_checksum_stats_request())]
+        table_stats_ids = [x.table_id for x in get_stats(self, ofp.message.table_stats_request())]
+        self.assertEquals(sorted(table_checksum_stats_ids), sorted(table_stats_ids))