Fix the legacy server.
Fix the legacy server.

We still support the legacy server on precise.
This branch fixes the regexp used to rewrite the path
for WebSocket requests to the Juju API.

The reason why the current regexp no longer works
is obscure, and we don't have time to investigate
the real cause now. However, the new regexp is
tecnically more correct and we can live with that for
the time being.

QA:
- bootstrap a precise env (e.g. ec2-precise);
- make deploy JUJU_ENV=ec2-precise SERIES=precise;
- juju set -e ec2-precise juju-gui builtin-server=fale;
- ensure you can connect to the GUI as usual.

R=jeff.pihach
CC=
https://codereview.appspot.com/122330043

juju/juju-gui-charm,juju/juju-gui-charm