Adds the my_ip value to the cinder.conf

This adds the my_ip value which is defaulting to the container address
which causes the iscsi mount problems. This is an issue in Juno +.

Change-Id: Ie1e3d4dbecad97e43a43bcd4ca404a3c30740bd0
Closes-Bug: 1398924
(cherry picked from commit a311a5e38b8a37b54577806d0a3ac05cc13fcf94)