Fix a bug in function destroyConnHashTable which frees a wrong pointer and

should cause SIGSEGV.
Signed-off-by: NPengzhou Tang <ptang@pivotal.io>

src/backend/cdb/motion/ic_udpifc.c

@@ -1720,7 +1720,7 @@ destroyConnHashTable(ConnHashTable *ht)
 			if (ht->cxt)
 				pfree(trash);
 			else
-				free(ht->table);
+				free(trash);
 		}
 	}
 
@@ -1728,6 +1728,9 @@ destroyConnHashTable(ConnHashTable *ht)
 		pfree(ht->table);
 	else
 		free(ht->table);
+
+	ht->table = NULL;
+	ht->size = 0;
 }
 
 /*