ogles 2 driver: Delete some dead code

grepping for IRR_COMPILE_GLES2_COMMON gives no other results

COGLESCoreExtensionHandler is only used through COpenGL3ExtensionHandler

irr/src/COpenGLCoreTexture.h

@@ -297,6 +297,7 @@ public:
 					delete[] tmpBuffer;
 				}
 #elif defined(IRR_COMPILE_GLES2_COMMON)
+				// TODO: revive this code
 				COpenGLCoreTexture *tmpTexture = new COpenGLCoreTexture("OGL_CORE_LOCK_TEXTURE", Size, ETT_2D, ColorFormat, Driver);
 
 				GLuint tmpFBO = 0;