The name implied that it was a surface in and of itself, rather than
parameters used by a helper to create a surface and view.
Rename it now that we have weston_curtain as a name, and clean up
initialisers.
Signed-off-by: Daniel Stone <daniels@collabora.com>
create_solid_color_surface actually returns a weston_view that it
creates internally. Since weston_solid_color_view is long and dull,
rename it to weston_curtain.
Signed-off-by: Daniel Stone <daniels@collabora.com>