Pull request to address issues Reynold Xin reported


1) The ConnectionManager change addresses an exception I saw in the logs as part of debugging issue reported by Reynold Xin.
The actual bug exists even with previous codebase - but due to the increased MT nature of spark post yarn fix, this might be more clearly manifesting now.

Either case, even if this is not the root cause, this needs to be addressed.

2) The run script change addresses an issue with setting up classpath.
Incorrect directory was being probed for shaded jar.


Please do let me know if this fixes the issues you saw Reynold.
In meantime, I am going to try to keep running tests under various loads to see if spark fails in any of them.

Thanks a lot for the concise testcase to help debug this !


Regards,
Mridul