netinfo: remove deprecated getaddr and getnetmask

In 5fa87504543719fdc827d2284738a7723b8a5973 we started using libnl
to retrieve both ipv4 addresses and netmask and these methods fell
into deprecation. It's time to get rid of this old ethtool using
code.

Change-Id: I33f39bb63ef440efb3b9bf00aa39f17f37813938
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/29600
Reviewed-by: Dan Kenigsberg <danken@redhat.com>