Add the distro-only flag.

Add the distro-only flag.

This can be used (e.g. in trusty) to
prevent quickstart from installing
the Juju stable PPA.

Tests: `make check`.

No QA required, I already tested this on
a trusty VM.

https://code.launchpad.net/~frankban/juju-quickstart/distro-only-flag/+merge/213021

(do not edit description out of merge proposal)

[frankban, 2014-03-27 11:09:52]

Please take a look.

[rharding, 2014-03-27 12:53:21]

LGTM thanks for the quick update.

[frankban, 2014-03-27 12:57:06]

*** Submitted:

Add the distro-only flag.

This can be used (e.g. in trusty) to
prevent quickstart from installing
the Juju stable PPA.

Tests: `make check`.

No QA required, I already tested this on
a trusty VM.

R=rharding
CC=
https://codereview.appspot.com/81400043

[frankban, 2014-03-27 12:59:29]

Hi Rick, thanks for the review!