Use print function for python3

Change-Id: Ib7eae9eaed6831fc74b06e02bdd0ca36e2e6c569
diff --git a/jeepyb/cmd/run_mirror.py b/jeepyb/cmd/run_mirror.py
index a76da7c..70a89c9 100644
--- a/jeepyb/cmd/run_mirror.py
+++ b/jeepyb/cmd/run_mirror.py
@@ -50,6 +50,7 @@
 # makes it suitable for running in a cron job with only stdout
 # redirected to a log, and also avoids one broken project preventing
 # caching of requirements for others.
+from __future__ import print_function
 
 import argparse
 import datetime
@@ -122,7 +123,7 @@
 
     def debug(self, msg):
         if self.args.debug:
-            print msg
+            print(msg)
 
     def process_http_requirements(self, reqlist, pip_cache_dir, pip):
         new_reqs = []