Validate force_host_copy API param for migration

For the force_host_copy parameter of volume migration, make sure that we
get a boolean or string that we can convert to boolean.

Change-Id: I7a77ca1780a4ef80bc351aa89df0efaaea0d7cf4
Closes-Bug: #1232698
Update Babel from Openstack Requirements

This is the update pushed to the global reqs.

Change-Id: I0d8ea330db3f9d68fee172302543b861cae4e013
Closes-Bug: 1233694
Merge "Update Babel from Openstack Requirements"
Merge "Validate force_host_copy API param for migration"