Introduce flake8-import-order

This commit introduces flake8-import-order to check import orders
automatically. We shouldn't do it manually.

Depends-On: Ia2140f5566ce169b076ffa5c9ebfbdbfc41e5bed
Change-Id: Iff75ebec42b295870edd1c04001adfb17460a682
diff --git a/tools/generate-tempest-plugins-list.py b/tools/generate-tempest-plugins-list.py
index 03e838e..acb29af 100644
--- a/tools/generate-tempest-plugins-list.py
+++ b/tools/generate-tempest-plugins-list.py
@@ -25,6 +25,7 @@
 
 import json
 import re
+
 import requests
 
 url = 'https://review.openstack.org/projects/'