Update py2 env path, remove py2 assert

qa/rpc-tests/getchaintips.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Copyright (c) 2014 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or https://www.opensource.org/licenses/mit-license.php .
@@ -7,7 +7,6 @@
 # on chains of different lengths, and join the network together again.
 # This gives us two tips, verify that it works.
 
-import sys; assert sys.version_info < (3,), ur"This script does not run under Python 3. Please use Python 2.7.x."
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal