backend-wayland: fix incorrect header
The wayland.c actually include 'xdg-shell-client-protocol.h' instead of the server one, so fix it. Otherwise, it's possible to get build failure due to race condition.
Signed-off-by: Chen Qi Qi.Chen@windriver.com Signed-off-by: Daniel Stone daniels@collabora.com [daniels: Found in OpenEmbedded/Yocto source.]