Zebra: Fix handling of larger table-ids

Zebra: Fix handling of larger table-ids

Zebra code was not handling larger table-ids correctly. There were 2 issues:

a) In the netlink interface, RTA_TABLE was never sent or processed. This
pretty much limited the table-ids that zebra could understand to < 255.

b) In the interface into the zebra RIB (in particular for protocols), there
were some incorrect checks that again assumed the table id should be < 252
or be "main". This is valid only for the Default VRF (for now), for other
VRFs, the table-id should be the value learnt from the kernel.

These two issues are addressed with this change.

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Ticket: CM-10087, CM-10091
Reviewed By: CCR-4359
Testing Done: Manual