Bump old CPI version v18->v25
Bump old CPI version v18->v25

v18 does not work with OpenStack Newton. v25 uses a fog version which supports Glance v2.x.

Signed-off-by: Jan von Loewenstein <f93d0758658406890bd0a32c473d6d4ec49c7582@sap.com>
cloudfoundry-incubator/bosh-openstack-cpi-release,cloudfoundry-incubator/bosh-openstack-cpi-release,cloudfoundry-incubator/bosh-openstack-cpi-release