Make `print` behave in Python 2 as in Python 3.

[vsapsai]

Summary

Currently the test "jenkins/test_monorepo_build.py" fails with Python 2 because
it expects the code print("@@@", name, "@@@") to print @@@ Build Directory @@@
while Python 2.7 treats the expression in parenthesis as a tuple and
prints ('@@@', 'Build Directory', '@@@')

zorg/jenkins/monorepo_build.py

 """Build and test clangs."""
 
+from __future__ import print_function
 import sys
 import logging
 import os
 import subprocess
 import datetime
 import time
 import argparse
 import shutil