[PATCH 10 of 10 ipv6 V2] runtests: add an IPv6 command line flag

[Jun Wu]

Excerpts from Martin von Zweigbergk's message of 2017-02-17 14:56:24 -0800:
> > Unused. Should I drop in flight?
> 
> I ended up doing that. This is now queued, thanks.

Thanks!

Sorry about the unused variable. I recently switched to gcc112 for faster
testing and it does not run pyflakes somehow - I will investigate and set
pyflakes up.

Thanks for moving the LOCALIP regexp between patches - I guess it was not
discovered because we have code to replace "127.0.0.1" to "* (glob)".