[netconfig] APT: Prefer ipv4 connections over ipv6

[netconfig] APT: Prefer ipv4 connections over ipv6

Ubuntu prefers ipv6 connections therefore in some networks, this
breaks software updates (it does a AAAA DNS lookup before A record
lookups). Let's prefer old style ipv4 connections over the new ipv6 in
order to save some processing and resource utilization.

Based on previous work from [1] (but without /etc/gai.conf, only APT).

[1] https://review.openstack.org/#/c/462502/

JIRA: FUEL-321

Change-Id: Ic3dff3baa1c0be9ac95972557d6a2d26641bfe1b
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>