Bump old cpi verison to 26 to support glance v2
Bump old cpi verison to 26 to support glance v2

[#139444439](https://www.pivotaltracker.com/story/show/139444439)

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