Add an additional 1 second sleep to after calling ggatec before calling

dd to defeat a race when writing out to the geom_gate(4) device

This will quell the Jenkins failure emails until I come up with a better
solution

MFC after: 1 month
Reported by: Jenkins
Sponsored by: EMC / Isilon Storage Division

tests/sys/geom/class/gate/1_test.sh

@@ -41,6 +41,7 @@ if ! ggatec create -p $port -u $us 127.0.0.1 /dev/$work; then
 	echo 'Bail out!'
 	exit 1
 fi
+sleep 1
 
 dd if=/dev/${src} of=/dev/ggate${us} bs=1m count=1
 sleep 1