network: Use self inflating bitmap for class IDs

network: Use self inflating bitmap for class IDs

Back in the day when I was implementing QoS for networks there
were no self inflating virBitmaps. Only the static ones.
Therefore, I had to allocate the whole 8KB of memory in order to
keep track of used/unused class IDs. This is rather wasteful
because nobody is ever gonna use that much classes (kernel
overhead would drastically lower the bandwidth). Anyway, now that
we have self inflating bitmaps we can start small and allocate
more if there's need for it.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>