Updated CI docs for image id failure
Updated CI docs for image id failure

R=frankban
CC=
https://codereview.appspot.com/9124043

mitechie/juju-gui,jrwren/juju-gui,mitechie/juju-gui,bac/juju-gui,CanonicalJS/juju-gui,bac/juju-gui,bac/juju-gui,mitechie/juju-gui,mitechie/juju-gui,bac/juju-gui,CanonicalJS/juju-gui,CanonicalJS/juju-gui,jrwren/juju-gui,jrwren/juju-gui,jrwren/juju-gui