misc/dashboard/builder: fixes and improvements
misc/dashboard/builder: fixes and improvements

- fix release upload
- add -rev= flag to build specific revision and exit
- added support for all-$GOARCH.bash

R=rsc
CC=golang-dev
http://codereview.appspot.com/2247044

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

tav/go,tav/go,tav/go,tav/go,tav/go,tav/go,tav/go