Modernize number literals

Use Python-3 compatible syntax, without breaking compatibility with py 2.7

- Octals literals start with 0o to prevent confusion
- The "L" at the end of large int literals is not required as they use
  long on Python 2 automatically.
- Using 'int' instead of 'long' for small numbers is OK in all cases except
  strict type checking checking, e.g. type(0).

https://fedorahosted.org/freeipa/ticket/4985

Reviewed-By: Jan Cholasta <jcholast@redhat.com>

ipaserver/install/bindinstance.py

@@ -922,7 +922,7 @@ class BindInstance(service.Service):
         # Make sure access is strictly reserved to the named user
         pent = pwd.getpwnam(self.named_user)
         os.chown(paths.NAMED_KEYTAB, pent.pw_uid, pent.pw_gid)
-        os.chmod(paths.NAMED_KEYTAB, 0400)
+        os.chmod(paths.NAMED_KEYTAB, 0o400)
 
         # modify the principal so that it is marked as an ipa service so that
         # it can host the memberof attribute, then also add it to the