Fix: sbd-inquisitor: Implement default delay start for diskless sbd

SBD sysconfig option SBD_DELAY_START is for addressing the case where cluster nodes reboot so fast even before fencing targeting it returns.
This could be common for virtual machines.
So far technically, a setting SBD_DELAY_START=yes takes effect only for sbd with shared disk, since the delay value is basically msgwait retrieved from sbd metadata.
For diskless sbd, for now we'd have to specify SBD_DELAY_START with a explicit delay value.
We need to implement to make SBD_DELAY_START=yes take effect for diskless sbd as well. In this case, the delay value should be SBD_WATCHDOG_TIMEOUT * 2