Running lang_update with tags present add new comments instead of updating existing ones

[flodolo]

Example.

Current comment in home.lang for en-GB

## NOTE: demo server for new home page is https://www-demo3.allizom.org/?v=1

Changed to

## NOTE: demo server for home page is https://www-dev.allizom.org/

After running lang_update the Korean file changes from this

## active ##
## promo_surfing ##
## promo_lightbeam ##
## NOTE: demo server for new home page is https://www-demo3.allizom.org/?v=1 ##
## NOTE: demo server for new home page is https://www-demo3.allizom.org/?v=1

To

## active ##
## promo_surfing ##
## promo_lightbeam ##
## NOTE: demo server for new home page is https://www-demo3.allizom.org/?v=1 ##
## NOTE: demo server for new home page is https://www-demo3.allizom.org/?v=1 ##
## NOTE: demo server for home page is https://www-dev.allizom.org

It doesn't seem to happen with only the active tag or the note.

[pascalchevrel]

should be fixed now