deleting / renaming git branches

[Graham Percival]

Could somebody please make
  dev/gperciva
be
  dev/waf?

I tried this a few months ago, and I thought that I'd done it
correctly, but dev/waf currently does not contain any waf-related
files.  I had a brief panic that I'd managed to lose all the
previous work on waf, but I found dev/gperciva still laying around
on my netbook, so I've pushed that again.

I have no appetite for playing more games with git after
(apparently) completely failing once.

Cheers,
- Graham