Update postinst

Author: JasonLG1979

raspotify/DEBIAN/postinst

@@ -3,8 +3,9 @@
 set -e
 
 # Secure the config file, there may be credentials in there
-if [ "$1" = "configure" ]; then
+if [ -f /etc/default/raspotify ]; then
     chmod 600 /etc/default/raspotify -f
+    chown root:root /etc/default/raspotify -f
 fi
 
 # Make sure `--linear-volume' is properly renamed