(font_family_registry): Even if FONTNAME conform to

(font_family_registry): Even if FONTNAME conform to
XLFD, if it specifies other fields than family and registry,
return FONTANME.  New argument FORCE if nonzero cancel that
feature.
(fontset_font_pattern): Call font_family_registry with FORCE 1 for
a signle byte character.  Don't set FAMILY part to nil here.  It
is handled by the caller choose_face_font.
(Fnew_fontset): Call font_family_registry with FORCE 0.
(Fset_fontset_font): Likewise.