Use the more proper -f. Leave /bin/rm in place since that's what

other rc scripts have, though it isn't strictly necessary.

etc/rc

@@ -132,9 +132,9 @@ done
 # Remove the firstboot sentinel, and reboot if it was requested.
 if [ -e ${firstboot_sentinel} ]; then
 	[ ${root_rw_mount} = "yes" ] || mount -uw /
-	/bin/rm ${firstboot_sentinel}
+	/bin/rm -f ${firstboot_sentinel}
 	if [ -e ${firstboot_sentinel}-reboot ]; then
-		/bin/rm ${firstboot_sentinel}-reboot
+		/bin/rm -f ${firstboot_sentinel}-reboot
 		[ ${root_rw_mount} = "yes" ] || mount -ur /
 		kill -INT 1
 	fi