Code review comment for lp://staging/~gary/juju-gui/login-ui

Land with changes suggested by Matthew.

Thanks Gary for your fixes to the test problems we were encountering
yesterday: this branch is really cool, and you did most of the work on
it anyway! :-)

As agreed, we (Nicola and I) will fix the remaining issues and land this
branch ourselves.

https://codereview.appspot.com/7060066/