update-notifier: "$package" string shouldn't be translated

[Sebastien Bacher]

Hey,

I'm updating the packages that don't use langpacks to include 
translations for raring.

The updated .po files for update-notifier were creating some issues 
because "$package", which is a variable name, got translated in a few 
locales when it shouldn't.

(ideally it shouldn't be in the translations template at all, but it 
seems a bit difficult to exclude since it's in the middle of a text 
description in a .data file and there is no way to filter it out or mark 
it as non translatable)

I've "reverted" the translations for that specific string, in the 
upload, for those locales:
am.po
crh.po
se.po
sr.po

It would be good if the string could also be fixed in launchpad by the 
corresponding translation teams

Thanks,
Sebastien Bacher