Devel is broken, we cannot release

[Ian Booth]

> 
> I think the problem is engineers are focused on there feature. They
> don't see the fallout from their changes. They may hope the fix will
> arrive soon, and that maybe someone else will fix it.
> 
> I propose a change in policy. When a there is a regression in CI, no
> new branches can be merged except those that link to the blocking bug.
> This will encourage engineers to fix the regression. One way to fix
> the regression is to identify and revert the commit that broken CI.
> 

Agree in principal. However, we have seen some issues on CI whereby the
unreliability of the underlying cloud has caused failures. So long as the issue
identified indeed has a root cause that we can fix in juju itself, then we
should block landings to trunk until it is fixed.