Make xar:format remove the new <originalMetadataAuthor> element

We introduced a new document property in 14.0, and it was added to the XAR format.

But it’s totally useless for an extension to expose this information, so I propose to get rid of it like we do for dates.

Among other things, it will fix the fact that we keep cherry-picking elements on 13.10.x branch, which produces warnings about this unknown element.

WDYT ?

+1 thanks

+1

+1

Sounds good.