Update docker-py to 0.5.3

Signed-off-by: Aanand Prasad <[email protected]>

requirements.txt

@@ -1,5 +1,5 @@
 PyYAML==3.10
-docker-py==0.5.0
+docker-py==0.5.3
 docopt==0.6.1
 requests==2.2.1
 six==1.7.3