gluon-core: use awk instead of grep+cut

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

@@ -16,7 +16,7 @@ mkdir -p "$VERSION_DIR"
 
 
 version_of() {
-	opkg status "gluon-$1" | grep '^Version: ' | cut -d' ' -f 2
+	opkg status "gluon-$1" | awk '/^Version: / { print $2 }'
 }
 
 oldversion_of() {