update the apt cookbook version
update the apt cookbook version

use new apt cookbook version ~> 2.7.0, since it supports debian 8 and
should work fine with everything else

Change-Id: Icc0b9973995b9fe945cd347d9f065d6a90a4be3d

openstack/cookbook-openstack-common,krtyyy/cookbook-openstack-common,krtyyy/cookbook-openstack-common,krtyyy/cookbook-openstack-common,tomzo/cookbook-openstack-common,tomzo/cookbook-openstack-common,tomzo/cookbook-openstack-common,openstack/cookbook-openstack-common