isort: format codebase

Change-Id: I6f11d123b68fd077f558d3c21349c55c5f251019
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/383715
Reviewed-by: Gavin Mak <gavinmak@google.com>
Tested-by: Mike Frysinger <vapier@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>

repo

@@ -254,11 +254,13 @@ import re
 import shutil
 import stat
 
+
 if sys.version_info[0] == 3:
-  import urllib.request
   import urllib.error
+  import urllib.request
 else:
   import imp
+
   import urllib2
   urllib = imp.new_module('urllib')
   urllib.request = urllib2