Merge pull request #3879 from mboersma/update-flake8

chore(client+controller): update flake8 to 2.4.1

Author: mboersma

dev_requirements.txt

@@ -2,7 +2,7 @@
 coverage>=3.7.1
 
 # Run "make flake8" to check python syntax and style
-flake8==2.4.0
+flake8==2.4.1
 
 # Used for mocking endpoints
 mock==1.0.1