dracut: fix typo in mount-zfs.sh.in

Format the `zpool get` command correctly.  The -o option must
be followed by "all" or the requested field name.

Reviewed-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #13602

contrib/dracut/90zfs/mount-zfs.sh.in

@@ -82,7 +82,7 @@ ZFS_DATASET="${ZFS_DATASET:-${root}}"
 ZFS_POOL="${ZFS_DATASET%%/*}"
 
 
-if ! zpool get -Ho name "${ZFS_POOL}" > /dev/null 2>&1; then
+if ! zpool get -Ho value name "${ZFS_POOL}" > /dev/null 2>&1; then
     info "ZFS: Importing pool ${ZFS_POOL}..."
     # shellcheck disable=SC2086
     if ! zpool import -N ${ZPOOL_IMPORT_OPTS} "${ZFS_POOL}"; then