hopefully fixed the OutOfMemoryError and NevativeArraySizeException

The DiskBasedCache is the Top crash in our application

![2014-12-15_11-48-33](https://cloud.githubusercontent.com/assets/1096485/5434279/73dede8c-8450-11e4-9631-822dd5fb12c9.png)

This fix comes from here: http://stackoverflow.com/questions/20916478/performance-issue-with-volleys-diskbasedcache