Add cinder::volume to cinder_controller when using Gluster

Having cinder::volume there is necessary when using the Gluster
backend. It used to be included in the controller after Gilles'
commits, but i erred when refactoring and removed it, so i'm putting
it back.
Honor parameter values for naming gluster volumes

$cinder_gluster_volume and $glance_gluster_volume parameters used to
affect only controller, but we should also use them in Gluster
backend. We need them synced if we want mounting on controller to
work.
Current cinder_controller also for Nova Network

Update parameter passing in nova_network::controller.
Sync defaults in seeds.rb with defaults in params.pp

Update the default names of Gluster volumes to match the ones in
params.pp (users can still override them if they want).

Not all defaults are synced. E.g. i think it doesn't make much sense
to provide default IP addresses of storage nodes, because the chance
that user could use these defaults is almost zero.
Merge pull request #49 from jistr/gluster_pt2

Gluster part 2