Shallow copy Device object into Operation object (#750168)

When Operation objects are created they take a copy of the Device object
to which the operation is to be applied.  The Device object includes a
vector of all the contained Partition objects currently on the device,
so these get copied too.

These additional deep copied Partition objects in the Operation object
are never accessed.  Therefore don't copy the contained Partition
objects when copying the Device object into the Operation object.

Bug 750168 - Reduce the amount of copying of partition objects