auth: Use luci-auth to get credentials.

Bug: 1001756
Change-Id: Ieab5391662e92ec9e2715a81fce2cef41717c2e3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1790607
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
diff --git a/git_cl.py b/git_cl.py
index ae6bcd5..cf784bb 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -538,7 +538,7 @@
   else:
     print('Warning: Some results might be missing because %s' %
           # Get the message on how to login.
-          (auth.LoginRequiredError(codereview_host).message,))
+          (auth.LoginRequiredError().message,))
     http = httplib2.Http()
 
   http.force_exception_to_status_code = True