There is inconsistent use of either `/usr/bin/python` or
`/usr/bin/env python`. This makes for unexpected results when a
user might be using a virtualenv.
Change-Id: Ibb030f920a8869f9113ade70b66a921cc815060d
docker engine 1.10 and docker engine 1.12 have different response for
list containers. Use status=running filter instead. It is provided by
all docker version.
Closes-Bug: #1658015
Change-Id: I54df4b08f215322d97d604ebd84e04255a359ef6