Updated openstack/openstack
Project: openstack/python-heatclient  7bbd75f98d2a80fd5dde6847eacd9fed05cb3285

Added timeout and rollback params in stack-preview

Added the support to specify timeout and enable_rollback
parameters to the stack-preview command.

Change-Id: Ifda2b6bdf2380ce22c6f2027ea8ee4e6e977cf60
Closes-Bug: #1335098