Fix multiple ipv4 addrs bug

[frenzymadness]

pifconfig is unable to show multiple IPv4 addresses attached to one interface - this is basically the same behavior as ifconfig command has but there is an old patch in RHEL which allows it so it might be a good idea to backport it here and provide the same functionality in all versions.

Example output in RHEL 7:

dummy0 HWaddr 66:78:8f:23:38:94
          inet addr:10.20.30.40 Bcast:10.20.30.255   Mask:255.255.255.255
          inet addr:10.20.30.45 Bcast:10.20.30.255   Mask:255.255.255.255
          inet addr:10.20.30.50 Bcast:10.20.30.255   Mask:255.255.255.255
	  inet6 addr: fe80::6478:8fff:fe23:3894/64 Scope: link
	  UP BROADCAST RUNNING NOARP

Example output with the newest ethtool:

dummy0
	HWaddr 6a:83:e2:25:65:69
	inet addr:10.20.30.40
	Bcast:10.20.30.255
	Mask:255.255.255.255
	inet6 addr: fe80::6883:e2ff:fe25:6569/64 Scope: link
	UP BROADCAST RUNNING NOARP

Output with merged patch:

dummy0
	HWaddr 22:ea:1d:9b:c9:e2
	inet addr:10.20.30.40 Bcast:10.20.30.255 Mask:255.255.255.255
	inet addr:10.20.30.45 Bcast:10.20.30.255 Mask:255.255.255.255
	inet addr:10.20.30.50 Bcast:10.20.30.255 Mask:255.255.255.255
	inet6 addr: fe80::20ea:1dff:fe9b:c9e2/64 Scope: link
	UP BROADCAST RUNNING NOARP

I'd say that the last one is the most readable because every IPv4/IPv6 record is on one line.

If you disagree, I'll have to maintain this patch in the new versions of RHEL to keep desired functionality.