protocol: move sub-surfaces to Wayland

This reverts commit 2396aec684.

This exact version of the sub-surface protocol has been copied into
Wayland core. Therefore it must be removed from here to avoid build
conflicts and useless duplication.

No other changes to sub-surface protocol consumers are needed, the
identical API is now offered by libwayland-client and libwayland-server.

The commit adding sub-surfaces to Wayland is:
Author: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

    protocol: add sub-surfaces to the core

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

tests/.gitignore

@@ -9,5 +9,3 @@ test-text-client
 wayland-test-client-protocol.h
 wayland-test-protocol.c
 wayland-test-server-protocol.h
-subsurface-client-protocol.h
-subsurface-protocol.c

tests/Makefile.am

@@ -91,9 +91,7 @@ weston_test_client_src =		\
 	weston-test-client-helper.c	\
 	weston-test-client-helper.h	\
 	wayland-test-protocol.c		\
-	wayland-test-client-protocol.h	\
-	subsurface-protocol.c		\
-	subsurface-client-protocol.h
+	wayland-test-client-protocol.h
 weston_test_client_libs =		\
 	$(SIMPLE_CLIENT_LIBS)		\
 	../shared/libshared.la		\
@@ -146,8 +144,6 @@ endif
 EXTRA_DIST = weston-tests-env
 
 BUILT_SOURCES =					\
-	subsurface-protocol.c			\
-	subsurface-client-protocol.h		\
 	wayland-test-protocol.c			\
 	wayland-test-server-protocol.h		\
 	wayland-test-client-protocol.h

tests/subsurface-test.c

@@ -23,7 +23,6 @@
 #include <string.h>
 
 #include "weston-test-client-helper.h"
-#include "subsurface-client-protocol.h"
 #include <stdio.h>
 
 #define NUM_SUBSURFACES 3