Bug in merging of collections

 session.execute("CREATE TABLE large(userid text PRIMARY KEY, properties map<int, text>) with compression = {}")
        for i in range(200):  # ensures partition size larger than compaction_large_partition_warning_threshold_mb                                                                                                               
            session.execute("UPDATE ks.large SET properties[%i] = '%s' WHERE userid = 'user'" % (i, get_random_word(strlen)))

        ret = session.execute("SELECT properties from ks.large where userid = 'user'")
        assert len(ret) == 1
	self.assertEqual(200, len(ret[0][0].keys()))