Fix watchquagga to watch just one daemon

Fix watchquagga to watch just one daemon

Ticket: CM-6669
Reviewed by: CCR-3249
Testing: See Bug

I believe in the past it made no sense to have only 1 quagga daemon running(zebra),
since it would just handle interface configuration and static routes, both of which
would be better handled through the linux cli.

Now that we have added recursive static routes and the ability to handle static
mpls labels to zebra, there are use cases where zebra would be the only be running.

This change allows watchquagga to behave with this setup.