Revert change in rev. 15955 because as Georg says:

Revert change in rev. 15955 because as Georg says:

This fix will create extra translator work, and nobody will remmeber that
bformat should be used instead of your solution once the real problem is
fixed. If you use from_ascii instead of from_utf8 everything is OK. utf8
can be wrong as encoding for files anyway, so for now we require that files
are pure ascii.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@15957 a592a061-630c-0410-9148-cb99ea01b6c8