interface. Without this, NFS_BOOT_NETMASK could be useless in
subnetting envirinment.
2. Comment out unneeded NFS swap related stuff.
Closes PR kern/3918.
The RPC/bootparamd calls to get the root and swap paths are now done
in nfs_boot_init() instead of nfs_boot_getfh(), so the latter now just
does the RPC/mountd call. Also changed some panics into error returns.
- Try V3 first for diskless booting. Fall back to V2 if V3 fails.
- optionally (option NFS_BOOT_TCP) try a TCP mount first
for diskless booting. Fall back to UDP if it fails.
- Enable switching between UDP and TCP for remounts.
