core: update console device on next run VM snapshot

* Added an 'EditableDeviceOnVmStatusField' annotation for
  'consoleEnabled' (in VmManagementParametersBase).
* Consequently, removed canDo validation in UpdateVmCommand.

Change-Id: I22a508327a678039eee666ea5f31748ee8c8f7b1
Bug-Url: https://bugzilla.redhat.com/1035289
Signed-off-by: Daniel Erez <derez@redhat.com>