Changed mesos-ps so that it runs on python2.6 or above.

From: Shingo Omura <everpeace@gmail.com>
Review: https://reviews.apache.org/r/14941
Modified mesos-execute so that it reports the framework id and task id.

From: Shingo Omura <everpeace@gmail.com>
Review: https://reviews.apache.org/r/15161