Adding Shark 0.7.1 to EC2 scripts
Merge pull request #39 from pwendell/master

Adding Shark 0.7.1 to EC2 scripts

This adds a newer version of Shark to the ec2 scripts. I've tested this for both Hadoop1 and Hadoop2 clusters.
Fix inconsistent and incorrect log messages in shuffle read path
Responses to review
Merge pull request #42 from pwendell/shuffle-read-perf

Fix inconsistent and incorrect log messages in shuffle read path

The user-facing messages generated by the CacheManager are currently wrong and somewhat misleading. This patch makes the messages more accurate. It also uses a consistent representation of the partition being fetched (`rdd_xx_yy`) so that it's easier for users to trace what is going on when reading logs.