Bump versions of linux headers in trusty OS image test

Signed-off-by: Maria Shaldibina <mshaldibina@pivotal.io>
Update bosh-agent

This includes a cherry-pick of a807749, which is an update to a timebomb
test.

Signed-off-by: Maria Shaldibina <mshaldibina@pivotal.io>
Convert openstack image to qcow2 0.10 compat

Signed-off-by: Maria Shaldibina <mshaldibina@pivotal.io>
Signed-off-by: Kris Hicks <krishicks@gmail.com>
Make instance type configurable in Openstack BATs

via BOSH_OPENSTACK_FLAVOR

Signed-off-by: Kris Hicks <krishicks@gmail.com>
Set net_id only if BOSH_OPENSTACK_NET_ID present

Signed-off-by: Kris Hicks <krishicks@gmail.com>
Merge branch '2719.2' into develop

Signed-off-by: Kris Hicks <krishicks@gmail.com>

Conflicts:
	go/src/github.com/cloudfoundry/bosh-agent
	stemcell_builder/stages/image_openstack_qcow2/apply.sh