[SPARK-1112, 2156] (0.9 edition) Use correct akka frame size and overhead amounts.

backport #1172 to branch-0.9.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #1455 from mengxr/akka-fix-0.9 and squashes the following commits:

a99f201 [Patrick Wendell] backport PR #1172 to branch-0.9