add opt out for autoupdates to git update init

init/30_update.sh

@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# opt out for autoupdates
+[ "$ADVANCED_DISABLEUPDATES" ] && exit 0
+
 pip install -U pyacoustid
 pip install -U pylast
 pip install -U flask