Refactor create_vm into smaller methods
Refactor create_vm into smaller methods

Signed-off-by: Max Becker <e6d855fe2263fd0035edb7e1f665a7466a1b4c9c@sap.com>

cloudfoundry-incubator/bosh-openstack-cpi-release,cloudfoundry-incubator/bosh-openstack-cpi-release,cloudfoundry-incubator/bosh-openstack-cpi-release