Do not import a pool that the kernel automatically imported

This works around the following upstream issue:
https://github.com/zfsonlinux/zfs/issues/714

Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>

defaults/initrd.scripts

@@ -654,7 +654,7 @@ startVolumes() {
 	
 	if [ "${USE_ZFS}" = '1' ]
 	then
-		if [ -z "${ZFS_POOL}" ];
+		if [ -z "${ZFS_POOL}" ]
 		then
 			good_msg "Importing ZFS pools"
 
@@ -667,6 +667,11 @@ startVolumes() {
 				bad_msg "Imported ZFS pools failed"
 			fi
 		else
+
+			if [ "$(zpool list -H -o name ${ZFS_POOL} 2>&1)" = "$ZFS_POOL" ]
+			then
+				good_msg "ZFS pool ${ZFS_POOL} already imported"
+			else
 				good_msg "Importing ZFS pool ${ZFS_POOL}"
 
 				/sbin/zpool import -N "${ZPOOL_FORCE}" "${ZFS_POOL}"
@@ -679,6 +684,7 @@ startVolumes() {
 				fi
 			fi
 		fi
+	fi
 }
 
 startiscsi() {