Revert "Add/expose VisualServer::get_default_clear_color()"

This reverts commit 753ba67d653c65239f0549313f3cca3330fd27f9,
in preparation from the merge of the gles3 branch, as the VisualServer
code changed too much to port this commit over during merge conflicts
resolution. It could be readded afterwards.

servers/visual/visual_server_raster.cpp

@@ -7612,11 +7612,6 @@ void VisualServerRaster::set_default_clear_color(const Color& p_color) {
 	clear_color=p_color;
 }
 
-Color VisualServerRaster::get_default_clear_color() const {
-
-	return clear_color;
-}
-
 void VisualServerRaster::set_boot_image(const Image& p_image, const Color& p_color,bool p_scale) {
 
 	if (p_image.empty())

servers/visual/visual_server_raster.h

@@ -1286,7 +1286,6 @@ public:
 
 	virtual void set_boot_image(const Image& p_image, const Color& p_color, bool p_scale);
 	virtual void set_default_clear_color(const Color& p_color);
-	virtual Color get_default_clear_color() const;
 
 	VisualServerRaster(Rasterizer *p_rasterizer);
 	~VisualServerRaster();

servers/visual/visual_server_wrap_mt.h

@@ -718,7 +718,6 @@ public:
 
 	FUNC3(set_boot_image,const Image& , const Color&,bool );
 	FUNC1(set_default_clear_color,const Color& );
-	FUNC0RC(Color,get_default_clear_color );
 
 	FUNC0R(RID,get_test_cube );
 

servers/visual_server.cpp

@@ -564,7 +564,6 @@ void VisualServer::_bind_methods() {
 	ObjectTypeDB::bind_method(_MD("free_rid"),&VisualServer::free);
 
 	ObjectTypeDB::bind_method(_MD("set_default_clear_color"),&VisualServer::set_default_clear_color);
-	ObjectTypeDB::bind_method(_MD("get_default_clear_color"),&VisualServer::get_default_clear_color);
 
 	ObjectTypeDB::bind_method(_MD("get_render_info"),&VisualServer::get_render_info);
 

servers/visual_server.h

@@ -1181,7 +1181,6 @@ public:
 
 	virtual void set_boot_image(const Image& p_image, const Color& p_color,bool p_scale)=0;
 	virtual void set_default_clear_color(const Color& p_color)=0;
-	virtual Color get_default_clear_color() const=0;
 
 	enum Features {
 		FEATURE_SHADERS,