Fix #34121: OSL + persistent images option was not freeing shader memory properly,

causing memory to increase continuously during animation render.

intern/cycles/render/shader.h

@@ -110,6 +110,8 @@ public:
 	static ShaderManager *create(Scene *scene, int shadingsystem);
 	virtual ~ShaderManager();
 
+	virtual void reset(Scene *scene) = 0;
+
 	virtual bool use_osl() { return false; }
 
 	/* device update */