Finding out interface type from interface name string is fragile. It is easily
broken, e.g. by biosdevname changing interface names to em<n> or p<n>*p<n>.
Sadly, Gentoo network configuration scripts are rather stupid, using format:
variable_${interface|mac|essid|apmac}.
http://www.gentoo.org/doc/en/handbook/2007.0/handbook-x86.xml?full=1#book_part4_chap2
The entries interface|mac|essid|apmac are basically indistinguishable. It's not
possible to say whether 'p1p1' is an interface or SSID, for example.
Fix the current behaviour a bit by checking whether the string is an interface.
If so, and it is not a Wi-Fi one, set the connection type as wired. Else it is
regarded as wireless.
