Retain 2 weeks of indexed Jenkins logs.

* modules/openstack_project/manifests/elasticsearch.pp: Update the cron
job that deletes old elasticsearch indexes to delete those more than two
weeks old instead of those more than one week old.

Change-Id: I9f3d615fcae96a6165860514e1e2c5e5584064f7
Reviewed-on: https://review.openstack.org/34417
Reviewed-by: Elizabeth Krumbach Joseph <lyz@princessleia.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins