CBQE-1277: add raise exception if rest hungs

Change-Id: Id720d12d691344cabe6de9fb7314c69bb9849fbf
Reviewed-on: http://review.couchbase.org/27106
Reviewed-by: Deepkaran Salooja <deepkaran.salooja@globallogic.com>
Tested-by: buildbot <build@couchbase.com>