Review Request: Fixed killtree to guard against session ids being reported as '0' by '/bin/ps' on OSX 10.8.

[Vinod Kone]

-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/9915/
-----------------------------------------------------------

Review request for mesos, Benjamin Hindman, Thomas Marshall, and Ben Mahler.


Description
-------

See summary.


Diffs
-----

  src/scripts/killtree.sh 1ec8efca2fd2c72208995cdf2f819ecb765f4c88 

Diff: https://reviews.apache.org/r/9915/diff/


Testing
-------

Tested on MacOSX10.8


Thanks,

Vinod Kone