(bug 41716) Add variant config to siprop=general

Parsoid again needs some extra information, this time so we can support
language variant conversion on our side of things. Added to properties to the
general siteinfo property.

Change-Id: I1ec7da2ec5b08228e74fec4fb366dae26cab8936
Merge "(bug 41716) Add variant config to siprop=general"