fixed scoping issue

src/renderers/webgl/WebGLShadowMap.js

@@ -100,6 +100,8 @@ function WebGLShadowMap( _renderer, _objects, maxTextureSize ) {
 
 		if ( lights.length === 0 ) return;
 
+		var currentRenderTarget = _renderer.getRenderTarget();
+
 		var _state = _renderer.state;
 
 		// Set GL state for depth map.