Update FilterFieldGenerator.java

In some cases I need to know name of property to create proper filtering field otherwise I am not able to create it for this specific property which isn't listed as container property id  - getContainerPropertyIds (for example: column generated based on some other properties - see colum status in the picture)
![example](https://f.cloud.github.com/assets/160366/1158369/6fa72b38-1fb3-11e3-8282-a4d03b66b76d.jpg)