daemon: streamline Quagga startup
daemon: streamline Quagga startup

Currently, all Quagga daemons are started concurrently by their
respective CORE services, using "quaggaboot.sh" generated by the
'zebra' service. However, all routing services depend on 'zebra'
already running, and 'vtysh' depends on ALL other Quagga services
before it can push configuration from the common "Quagga.conf" to
all running daemons (see "waitforvtyfiles()" in "quaggaboot.sh").

The spinwait+timeout based implementation of "waitforvtyfiles()"
may, depending on load, give up too early and fail to configure
all Quagga daemons.

This patch streamlines the way Quagga daemons are started, by
launching them all from the 'zebra' service. The correct sequence
is to first launch the 'zebra' daemon itself, then proceed with
all routing daemons, and finish with a call to "vtysh -b" which
configures all running daemons.

The list of all applicable daemons to launch is obtained using
'grep' from Quagga.conf, in the same way "waitforvtyfiles()" used
to discover which *.vty files to look for in /var/run/quagga/.

The startup command for all services other than 'zebra' becomes
empty, and "quaggaboot.sh" issues a warning on attempts to have
it launch any other daemon.

Signed-off-by: Gabriel Somlo <21ac1e587e9b684f27b1dd7bb0c255340ad5fde8@cert.org>

coreemu/core,coreemu/core,coreemu/core,coreemu/core