Configuring bonded slaves without configuration

- Each bonded slave has to have bootproto=dhcp
- Already configured interfaces are skipped
- Lacks reporting to user, TBD
Catching errors, informing user

- Catching also race conditions between two instances of WebYast
  or WebYast and Classical YaST
Merge pull request #58 from kobliha/Webyast-1.3

Configuring bonded slaves without configuration