Add netlink hooks to delete a bridge dev #44

Signed-off-by: Dhammika Pathirana <dhammika@gmail.com>


Closes #44 

Docker-DCO-1.1-Signed-off-by: Dhammika Pathirana <dhammika@gmail.com> (github: dhammika)
Good catch, we weren't null terminating IFNAMSIZ str. 
There are couple of other places too, I'll send a different pull for those.
I'm not sure if we need to check name string length though, since we can't create a bridge with same string.