Remove bundler validation warning
Remove bundler validation warning

- The validation message from Rubygems was:
  ["README.md", "USAGE.md"] are not files
- using the 'Dir[pattern, ...]' and checking
  for file existence doesn not produce
  a warning massage if files do not exist

Signed-off-by: Tom Kiemes <2e6bc7bf64c2cabd57fd2be0c1baf57f97b6fecc@sap.com>

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