Increase rsyslog buffer sizes.
Increase rsyslog buffer sizes.

Swift proxy logs to syslog during the devstack-gate tempest runs. To
better capture the swift logs increase the rsyslog buffer size to 6k
bytes allowing for longer messages like tracebacks.

This was setup by openstack-infra previous during our diskimage
builds.

  I03e42964e14d9f930c07ed047851bdf775639c59

Change-Id: Iaa232335865410600c93f47d4777ed4f1bce08e2
Signed-off-by: Paul Belanger <e7139c8e6c4ea75cc1c287ce081b2dc0f3ab39ec@redhat.com>

dtroyer/devstack,richliu/devstack,openstack-dev/devstack,nawawi/openstack,noironetworks/devstack,nawawi/openstack,dtroyer/devstack,group-policy/devstack,noironetworks/devstack,openstack-dev/devstack,group-policy/devstack,richliu/devstack