Trim excess shellcheck annotations. Widen to all non-Korn scripts

Before, make shellcheck checked
  scripts/{commitcheck,make_gitrev,man-dates,paxcheck,zfs-helpers,zfs,
           zfs-tests,zimport,zloop}.sh
  cmd/zed/zed.d/{{all-debug,all-syslog,data-notify,generic-notify,
                 resilver_finish-start-scrub,scrub_finish-notify,
                 statechange-led,statechange-notify,trim_finish-notify,
                 zed-functions}.sh,history_event-zfs-list-cacher.sh.in}
  cmd/zpool/zpool.d/{dm-deps,iostat,lsblk,media,ses,smart,upath}
now it also checks
  contrib/dracut/{02zfsexpandknowledge/module-setup,
                  90zfs/{export-zfs,parse-zfs,zfs-needshutdown,
                         zfs-load-key,zfs-lib,module-setup,
                         mount-zfs,zfs-generator}}.sh.in
  cmd/zed/zed.d/{pool_import-led,vdev_attach-led,
                 resilver_finish-notify,vdev_clear-led}.sh
  contrib/initramfs/{zfsunlock,hooks/zfs.in,scripts/local-top/zfs}
  tests/zfs-tests/tests/perf/scripts/prefetch_io.sh
  scripts/common.sh.in
  contrib/bpftrace/zfs-trace.sh
  autogen.sh

Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12042

cmd/fsck_zfs/fsck.zfs.in

@@ -26,15 +26,15 @@ for dataset in "$@"; do
 
 	case "$(@sbindir@/zpool list -Ho health "$pool")" in
 		DEGRADED)
-			ret=$(( $ret | 4 ))
+			ret=$(( ret | 4 ))
 			;;
 		FAULTED)
 			awk '!/^([[:space:]]*#.*)?$/ && $1 == "'"$dataset"'" && $3 == "zfs" {exit 1}' /etc/fstab || \
-				ret=$(( $ret | 8 ))
+				ret=$(( ret | 8 ))
 			;;
 		"")
 			# Pool not found, error printed by zpool(8)
-			ret=$(( $ret | 8 ))
+			ret=$(( ret | 8 ))
 			;;
 		*)
 			;;

cmd/zed/zed.d/zed-functions.sh

@@ -263,7 +263,7 @@ zed_notify_email()
                 -e "s/@SUBJECT@/${subject}/g")"
 
     # shellcheck disable=SC2086
-    eval "${ZED_EMAIL_PROG}" ${ZED_EMAIL_OPTS} < "${pathname}" >/dev/null 2>&1
+    ${ZED_EMAIL_PROG} ${ZED_EMAIL_OPTS} < "${pathname}" >/dev/null 2>&1
     rv=$?
     if [ "${rv}" -ne 0 ]; then
         zed_log_err "$(basename "${ZED_EMAIL_PROG}") exit=${rv}"

cmd/zvol_wait/zvol_wait

@@ -20,6 +20,7 @@ filter_out_deleted_zvols() {
 	OIFS="$IFS"
 	IFS="
 "
+	# shellcheck disable=SC2086
 	zfs list -H -o name $zvols 2>/dev/null
 	IFS="$OIFS"
 }