fix: elasticsearch should not dump its heap to its log_dir

1. In reference to IT-11, elasticsearch previously dumped its heap
to /var/log/elasticsearch if it OOMs, which can cause the root partition
to fill up.
2. Although with SRP v6.0 all log_dirs are now attached to ephemeral drive,
the heap should *not* get mixed in with logs and will cause other unwanted
issues. Thus, reasoning for dumping heap to /data volume.

Squashed commit of the following:

commit b76ebac7d38f1751df659f2a1912d54ec6505f7a
Author: Rachel McCuistion <rachel@infochimps.com>
Date:   Fri Mar 7 13:09:58 2014 -0600

    elasticsearch should not dump its heap witin its log_dir

Change-Id: I799ab4554a01a5e253f6a04d065eddb485e0addd