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/find_stack_traces.py b/tools/find_stack_traces.py
index f2da27a..2ba8b16 100755
--- a/tools/find_stack_traces.py
+++ b/tools/find_stack_traces.py
@@ -18,9 +18,10 @@
 import gzip
 import pprint
 import re
+import sys
+
 import six
 import six.moves.urllib.request as urlreq
-import sys
 
 
 pp = pprint.PrettyPrinter()