Fix network attributes to conform to the new attrib scheme.

Make sure that generated network roles have the right attribute
dependencies, and export an attribute that contains all the
information for a given network.
Merge pull request #255 from VictorLowther/pull-req-master-dccf04341e8a02b81a47fd321efe6c0256033410

+2 
CB 2: Make all the things use wants-attrib for smart attribute injection. [2/8]