Use lower() on LC_MESSAGES only if it is a string and not None
Use lower() on LC_MESSAGES only if it is a string and not None

Resolves: https://github.com/mike-fabian/ibus-table/issues/130
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2131410

mike-fabian/ibus-table,kaio/ibus-table,kaio/ibus-table,mike-fabian/ibus-table