[DRE-maint] Bug#979432: ruby-rack FTBFS on IPV6-only buildds

[Chris Hofstaedtler]

Control: found -1 2.1.4-1
Control: tags -1 - unreproducible

* Chris Hofstaedtler <zeha at debian.org> [210207 18:19]:
> Thanks. However that info appears outdated, as on a current Debian
> unstable, I always get a `lo` interface with 127.0.0.1 and ::1
> bound. The tests want 127.0.0.1, so that works.
> 
> Without more info on how the buildd setup looks like, I cannot
> reproduce this. Or maybe the failure has gone anyway?

So, if I actually do this:
   ip a del 127.0.0.1/8 dev lo

Then the tests indeed crash.

But now that modern kernels apparently always hand one a working
"127.0.0.1", do we really want to bother with this?

I guess one can change all the tests to use ::1 instead of
127.0.0.1, but that will just introduce other failure modes.

Chris