Ryzom checks for 0 allocated AGP/Video RAM, so lie max. here instead of saying 0.

--HG--
branch : gsoc2013-dfighter

code/nel/src/3d/driver/OpenGL3/driver_opengl.h

@@ -332,8 +332,8 @@ public:
 	virtual bool			copyTextToClipboard(const ucstring &text);
 	virtual bool			pasteTextFromClipboard(ucstring &text);
 
-	uint32 getAvailableVertexAGPMemory (){ return 0; };
-	uint32 getAvailableVertexVRAMMemory (){ return 0; };
+	uint32 getAvailableVertexAGPMemory (){ return uint32( -1 ); };
+	uint32 getAvailableVertexVRAMMemory (){ return uint32( -1 ); };
 
 	virtual emptyProc		getWindowProc();