[PATCH 3 of 6] debugcommands: move 'debuglabelcomplete' in the new module

[Augie Fackler]

> On Feb 13, 2017, at 14:24, Augie Fackler <raf at durin42.com> wrote:
> 
>> Meant to be removed from commands.py too, right?
> 
> Looks like it. I've queued patches 1,2, 4-6 of this series, we can get
> this one on a resend.

Sigh. I'm getting test-completion.t failures with these applied, so I'm going to discard them for now.