make force-tag gone

[Bastien Nocera]

On Tue, 2008-09-09 at 09:46 -0700, Jesse Keating wrote:
> On Tue, 2008-09-09 at 18:03 +0200, Denis Leroy wrote:
<snip>
> MikeB said that he'd look into some CVS/make changes that would allow
> checking koji for an on going or successful build of a tag/n-v-r before
> allowing a force-tag.  This would allow folks to force-tag before having
> a successful build, but would not allow you to force the tag after a
> successful build, or while a build is still going with that n-v-r.

It should also disallow force tagging if a build is already in flow.
Bonus points if it gives the opportunity to cancel the build in the same
move as well.