This patch slightly modifies the order of operations in the euca exercise
script. It moves the deletion of the security group to the end, after
the instance has been terminated. The reason this change must be made
is because of this change proposed to nova:
https://review.openstack.org/#change,4154
Without this change, when exercise.sh is run against this patch, the euca
exercises will fail when the security group is deleted. Moving it to the
end should make it pass, as the security group will no longer be in use.
Change-Id: I9095a02c42173ed1837ec20b38d5ef00fe4474ec