Initialize pointer before passing to e_wheel_bindings_find()

It's going to dereference it, so init it to NULL.

src/bin/e_bindings.c

@@ -1225,7 +1225,7 @@ E_API E_Action *
 e_bindings_wheel_event_handle(E_Binding_Context ctxt, E_Object *obj, E_Binding_Event_Wheel *ev)
 {
    E_Action *act;
-   E_Binding_Wheel *binding;
+   E_Binding_Wheel *binding = NULL;
 
    if (bindings_disabled) return NULL;
    while (1)