Use 'stat' package instead of literals for mkdir()

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

Change-Id: Ic988ad181d32357d82dfa554e70d8525118334c0

repo

@@ -88,6 +88,7 @@ REPO_MAIN = S_repo + '/main.py' # main script
 import optparse
 import os
 import re
+import stat
 import subprocess
 import sys
 import urllib2
@@ -276,7 +277,7 @@ def _SetupGnuPG(quiet):
 
   if not os.path.isdir(gpg_dir):
     try:
-      os.mkdir(gpg_dir, 0700)
+      os.mkdir(gpg_dir, stat.S_IRWXU)
     except OSError as e:
       print >>sys.stderr, \
             'fatal: cannot make %s directory: %s' % (