Set dynamicTriggerConfiguration switch

In Jenkins version 1.490 with Gerrit Trigger plugin
1.6.0 the dynamicTriggerConfiguration flag
needs to be explicitly turned off in order for the
triggers defined within the job to work properly.

Change-Id: If5835e933b812a7fe17c49f0f6988360f7154f80
Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>
Reviewed-on: https://review.openstack.org/36226
Reviewed-by: Arnaud Fabre <fabre.arnaud@gmail.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Khai Do <zaro0508@gmail.com>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins