Fix gate for docker 1.10

Docker 1.10 has broken the gate and this patch will correct that
breakage.

The issue comes with rsyslog. Due to a commit in Docker 1.10 [1] we
must change the way we get the log socket for rsyslog. The /dev/
folder will no longer populate as we used it. So instead we simply
make a new socket in a path we control and share that to the correct
location in the containers.

Additionally, adjust the gate for new Docker daemon.

[1] https://github.com/docker/docker/pull/16639
Partially-Implements: blueprint kolla-upgrade
Change-Id: I881a2ecdf6d7b35991e1d38a3f3e60d022d6577f