Merge gating for more juju subprojects

[Martin Packman]

On 13/03/2015, Martin Packman <martin.packman at canonical.com> wrote:
>
> That said, if there are any packages you think we should *not* gate
> landings on their test suite passing yet, please say now.

With the lack of objections, I've gone ahead and made the more active
projects in the juju namespace on github merge gated.

>From now on, to land branches for:

    juju/errors
    juju/loggo
    juju/names
    juju/testing
    juju/utils

Add "$$merge$$" in a comment on the pr and wait for the bot to run tests.

Please poke me if you notice anything amiss.

Martin