names/user: Update regex

names/user: Update regex

Update username regex to allow launchpad
usernames, which use the following regex:
r"^[a-z0-9][a-z0-9\+\.\-]+$"

https://code.launchpad.net/~waigani/juju-core/change-user-regex/+merge/220896

(do not edit description out of merge proposal)

[waigani, 2014-05-26 02:23:54]

Please take a look.

[fwereade, 2014-05-26 07:11:46]

What's the motivation here?

[fwereade, 2014-05-27 13:23:02]

On 2014/05/26 07:11:46, fwereade wrote:
> What's the motivation here?

We discussed this, but I don't recall what conclusion we came to. IMO this is
the internal juju name, and we don't want to let external auth providers affect
it -- we can't just keep on changing the regex as we get new ones. I'm open to
the idea that we want a *different* regex, but I think that's about the display
name for juju (and depends on the schema change to use something else as the
_id, I think). WIP for now?