Bug 834568: self-test on failure, related changes

In addition to self-testing on failure, this does a bunch of little things:
 * eliminate the free state
 * show requests in the lifeguard UI (with API change)
 * makes failed-request states expirable
 * eliminates the now-unnecessary 'closing' request state
 * power-cycles during the sut_verifying process, per dividehex's suggestion