Add posargs possibility in tox
Add posargs possibility in tox

According to tox documentation it is possible to define a default
command line if no posargs are provided to tox.

This patch allow the developer to customize the tox command call in
order to pass arguments to the underlying command.

Example: tox -epy27 -- -q server
Which will run the tests silently only for the server directory.

Change-Id: I0c358f4f9cea4abf8cc5a4c486fa8425ce30ce20

goneri/dci-control-server,goneri/dci-control-server,enovance/dci-control-server,enovance/dci-control-server,goneri/dci-control-server,redhat-cip/dci-control-server,goneri/dci-control-server,redhat-cip/dci-control-server