Akka bug fix in scala 2.10

commit to be reviewed @5b11028

This can solve the problem I have stated in #211 but there are some doubts about it. 

1. What would be the copyright license of SparkActorSystem.scala since I have copied some code from Akka lib.

2. It is tested and worked as expected on the lines of behavior with akka 2.0 library. With one doubt that it is possible for ActorSystem to hang (chance of 1 in 100) only when there is a fatal exception like OOM inside akka lib.