MB-100: print UI logs for autofailover failed tests

Change-Id: Idd6151258830636eba73c2473ea1dde1bf8d7a7b
Reviewed-on: http://review.couchbase.org/24384
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>