Merge pull request #2910 from mboersma/update-py-dateutil

chore(client): update python-dateutil to 2.4.0

Author: mboersma

dev_requirements.txt

@@ -1,6 +1,6 @@
 # Deis client requirements
 docopt==0.6.2
-python-dateutil==2.2
+python-dateutil==2.4.0
 requests==2.5.1
 termcolor==1.1.0