ruby-ipaddress: new debian version (fix FTBFS with ruby2.0 #720251)

[David Suárez <david.sephirot@gmail.com>]

Hi,

I have updated ruby-ipaddress to a new debian version.

Some comments:
  - Fix some tests failing with ruby 2.0 due to some literal strings encoding 
(fix FTBFS #720251).
  - Bump standards version to 3.9.4; no changes needed

It builds fine on a sid chroot.

Can anyone review and upload it.

Thanks,

David