Adjust netGetNetmask for new net-tools output, switch netGetIp from ifconfig to ip

Adjust netGetNetmask for new net-tools output, switch netGetIp from ifconfig to ip

ifconfig from net-tools until 1.60-27 looked like:

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:74133 errors:0 dropped:0 overruns:0 frame:0
          TX packets:74133 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:7122434 (6.7 MiB)  TX bytes:7122434 (6.7 MiB)

Starting with net-tools 1.60+git20150829.73cef8a-1 it looks like:

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

So we need to adjust ifconfig parsing accordingly.
There's no need to use ifconfig for netGetIp, so switch to ip(8) while at it.

Thanks: karlh1 + Patrick Neumann for the bug report
Closes grml/grml#65