We need to mount /dev both Libvirt and Cinder containers and
/dev/pts is not correctly mounted.  The /dev/pts recieves no
permissions from the host so it becomes inacessable.
We need to change the permissions of /dev/pts in the container
to 666.

Change-Id: Id197a766adc3aecb24e6b10aa84f51c23124b488
Closes-bug: #1468951