Don't check alpha value before adding gradient color stops
Don't check alpha value before adding gradient color stops

cairo_pattern_add_color_stop_rgb() calls
cairo_pattern_add_color_stop_rgba() with alpha = 1, so we can always use
cairo_pattern_add_color_stop_rgba().

GNOME/libgxps,GNOME/libgxps,GNOME/libgxps