Add "openstack server unshelve" into OSC
Add "openstack server unshelve" into OSC

The unshelve operation is not supported by OSC,
and this patch tries to add it.

Change-Id: Ic60a4616cb63ad21c1a3c8e02611da8bad3a8bd0
Implements: blueprint introduce-shelve-into-osc

dtroyer/osc-lib