gluon-core: clean up upgrade main script

gluon/gluon-core/files/etc/uci-defaults/zzz-gluon-upgrade

@@ -13,27 +13,20 @@ version_of() {
 }
 
 oldversion_of() {
-	oldversion="$(cat "$VERSION_DIR"/"$1" 2>/dev/null)"
-
-	# Legacy support
-	if [ -z "$oldversion" ]; then oldversion="$(cat /etc/.freifunk_version_keep 2>/dev/null)"; fi
-	if [ -z "$oldversion" ]; then oldversion="$(cat /etc/.lff_version_keep 2>/dev/null)"; fi
-	if [ -z "$oldversion" ]; then oldversion="$(cat /etc/.kff_version_keep 2>/dev/null)"; fi
-
-	echo "$oldversion"
+	cat "$VERSION_DIR"/"$1" 2>/dev/null
 }
 
 do_dir() {
-	if [ -d "$1" ]; then
-		local s
-		for s in "$1"/*; do "$s"; done
-	fi
+	[ -d "$1" ] || return
+
+	local s
+	for s in "$1"/*; do "$s"; done
 }
 
 do_component() {
 	local component="$1"
 	local version="$(version_of "$component")"
-	if [ -z "$version" ]; then continue; fi
+	[ "$version" ] || continue
 
 	(
 		cd "$component"
@@ -45,7 +38,7 @@ do_component() {
 			local v
 
 			for v in *; do
-				if [ "$v" = initial -o "$v" = invariant -o "$v" = version ]; then continue; fi
+				[ "$v" != initial -a "$v" != invariant ] || continue
 
 				# The return value of opkg compare-versions is negated
 				if ! opkg compare-versions "$v" '>>' "$oldversion"; then
@@ -61,21 +54,11 @@ do_component() {
 }
 
 
-version="$(version_of core)"
-
-oldversion="$(cat "$VERSION_FILE" 2>/dev/null)"
-if [ -z "$oldversion" ]; then oldversion="$(cat "$VERSION_FILE_FREIFUNK" 2>/dev/null)"; fi
-if [ -z "$oldversion" ]; then oldversion="$(cat "$VERSION_FILE_LFF" 2>/dev/null)"; fi
-if [ -z "$oldversion" ]; then oldversion="$(cat "$VERSION_FILE_KFF" 2>/dev/null)"; fi
-
 cd "$UPGRADE_DIR"
 
 do_component core
 
 for component in *; do
-	if [ "$component" != 'core' ]; then
-		do_component "$component"
-	fi
+	[ "$component" != 'core' ] || continue
+	do_component "$component"
 done
-
-rm -f "$VERSION_FILE_FREIFUNK" "$VERSION_FILE_LFF" "$VERSION_FILE_KFF"