buildrepo: purge old pkgs before generate index

and generate index if it is missing, even if all packages are up2date.

buildrepo

@@ -44,6 +44,9 @@ build() {
 
 	cd "$aportsdir/$repo" || return 1
 	mkdir -p "$repodir/$repo"
+	if ! [ -f "$repodir/$repo"/APK_INDEX.gz ]; then
+		indexupdate="APK_INDEX.gz"
+	fi
 
 	# first we try copy everything possible and find out which we need
 	# to rebuild. By doing this we might save us for rebuilding 
@@ -79,6 +82,9 @@ build() {
 		done
 	fi
 
+	# kill old packages in repo
+	purge "$repo"
+
 	# generate the repository index
 	cd "$repodir/$repo"
 	echo ">>> Generating Index for $repo..."
@@ -90,9 +96,6 @@ build() {
 		done
 		apk $deps index *.apk | gzip -9 > APK_INDEX.gz
 	fi
-
-	# kill old packages in repo
-	purge "$repo"
 }
 
 while getopts "a:d:hl:pr:" opt; do