engine: fix instance types permissions

If the VM is created from instance type, the user needs to have either
create instance permission on the specific instance type or the proper
getActionType().getActionGroup() on it (either is OK).

Same comes for image type.

Change-Id: Ibf039b0ea2d4488e243416832703bfc6a55b7337
Signed-off-by: Tomas Jelinek <tjelinek@redhat.com>