Add support for relating vault to etcd to support HA deployments of vault. Depends-On: Iebb2415077b682dfdf590b4b5f35a3c593ed3d69 Depends-On: I05a04bdc237b2a698b2f2d29e18c5a33510a2513 Change-Id: I161db8296031776652425f563a11de3ee8f7f86e