Change print statements to work in python3

This is part of a series of changes to introduce Python3 support.

Change-Id: I373be5de7141aa127d7debdbce1df39148dbec32

editor.py

@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import os
 import re
 import sys
@@ -53,10 +54,10 @@ class Editor(object):
       return e
 
     if os.getenv('TERM') == 'dumb':
-      print >>sys.stderr,\
+      print(
 """No editor specified in GIT_EDITOR, core.editor, VISUAL or EDITOR.
 Tried to fall back to vi but terminal is dumb.  Please configure at
-least one of these before using this command."""
+least one of these before using this command.""", file=sys.stderr)
       sys.exit(1)
 
     return 'vi'
@@ -67,7 +68,7 @@ least one of these before using this command."""
 
        Args:
          data        : the text to edit
-  
+
       Returns:
         new value of edited text; None if editing did not succeed
     """