update-kernel: Use policy to detect available packages (list)

It's much slower but works even if `apt-scripts' is not installed.

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>

update-kernel

@@ -166,16 +166,13 @@ if [ -n "$list" ]; then
 	echo "List of available kernels${kernel_flavour:+ for $kernel_flavour flavour}:"
 	list_files=$(mktemp)
 	rpm -qa --queryformat '[%{=NAME}\t%{FILENAMES}\n]' 'kernel-*' > "$list_files"
-	list_extras=$(mktemp)
 	set -o pipefail
-	apt-cache list-extras 2>/dev/null | sort > "$list_extras" && extras=1 || extras=
 	apt-cache pkgnames "kernel-image-${kernel_flavour}" | sort \
-	| join -a1 -o1.1,2.1 - "$list_extras" \
 	| sort -V \
 	| grep '#' \
 	| grep -v -e '-debuginfo#' -e '^kernel-image-domU-' \
 	| (
-	  while read -r k j; do
+	  while read -r k; do
 		pkg=${k%#*}
 		flv=${pkg#kernel-image-}
 		ev=${k#*#}
@@ -186,7 +183,8 @@ if [ -n "$list" ]; then
 		ver=${ver%-*}
 		ev=$epo$ver
 
-		[ -z "$extras" ] || [ -n "$j" ] && echo -n "   " || echo -n "  *"
+		pkglist=$(apt-cache policy "$k" | grep -w 'pkglist$')
+		[ -z "$pkglist" ] && echo -n "   " || echo -n "  *"
 		echo -n " $pkg-$ver-$rel"
 		if rpm -q "$pkg-$ver-$rel" >/dev/null 2>&1; then
 			if [ "$def" = "$ver-$flv-$rel" ]; then
@@ -194,7 +192,7 @@ if [ -n "$list" ]; then
 			else
 				echo -n ' [installed]'
 			fi
-		elif [ -n "$extras" ] && [ -z "$j" ] && [ "$rflv" = "$flv" ]; then
+		elif [ -n "$pkglist" ] && [ "$rflv" = "$flv" ]; then
 			echo -n " <--- upgrade"
 		fi
 		[ "$rrel" = "$ver-$flv-$rel" ] && echo -n ' RUNNING'
@@ -224,10 +222,9 @@ if [ -n "$list" ]; then
 	if [ $count -eq 0 ]; then
 		echo "Nothing found."
 	else
-		[ -n "$extras" ] && echo "[*] Latest available in repo."
+		echo "[*] Latest available in repo."
 	fi
 	)
-	rm -f -- "$list_extras"
 	exit 0
 fi