Shuffle may not shutdown in case of a fetch failure, causing it to hang

When running the Cascading tests with 0.8-alpha, they hang forever.

git clone https://github.com/cascading/cascading
cd cascading

update cascading-hadoop2-tez/build.gradle:

• update ext.tezVersion to '0.8.0-alpha'
• add the staging repos to the repositories block.

 maven {url = 'https://repository.apache.org/content/repositories/orgapachetez-1040/'}
 maven {url = 'https://repository.apache.org/content/repositories/orgapachetez-1041/'}

then run this:

gradle cascading-hadoop2-tez:build -i

It will hang after a while. You will have to have gradle 2.x installed on your machine. 1.x wont work.