Generate proper bridge port configuration

bnc#879617

* Removed workaround for sysconfig (0.0.0.0/32).
* Huge cleanup.
* Updates for testsuite
more ruby code:
```
  @Items.rassoc(device).first
```
for details see http://www.ruby-doc.org/core-2.0/Hash.html#method-i-rassoc