Generate proper bridge port configuration

bnc#879617

* Removed workaround for sysconfig (0.0.0.0/32).
* Huge cleanup.
* Updates for testsuite
I'll stay with select. ```find``` needs some more handling when nothing is found. ```@Items``` usually contains less then 10 items (number of various net devices in the system) so ```select```'s overhead is not that big.