recent updates to fw_update to support multiarch causing fw_update to fail in mkchroot.sh

this line of code in a recent update to /usr/sbin/fw_update to derive VTYPE is causing mkchroot.sh to fail with sed: 0: /var/run/dmesg.boot: No such file or directory

which of course has NOT been created at this point..(system never has booted) for a workaround and since I am NOT cross building I will simply copy said file from the build host into the chroot as a workaround) but needs a better solution I feel..

VTYPE=$( sed -n "/^OpenBSD VNAME([^ ]*).*/s//\1/p"
/var/run/dmesg.boot | sed '$!d' ) [[ $VTYPE == -!(stable) ]] && HTTP_FWDIR=snapshots