Add timestamps to JJB jobs.

When the timeout wrapper is overridden to increase the default timeout
in Jenkins Jobs we need to specify that timestamps should be set as the
default to use timestamps is overridden as well.

Change-Id: I7fd55f14c647f6ff97741108fb6768ddad3b448e
Reviewed-on: https://review.openstack.org/30003
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