newton-10.0 plugin support for example plugins

Detailed bug description:
 Fuel example plugins do not support newton-10.0 release.
Steps to reproduce:
 Install 10.0 ISO #123
Expected results:
 Plugin should be available to install on 10.0 environment.
Actual result:
 Incompatible with this release.
Reproducibility:
 <put your information here>
Workaround:
 Modify metadata.yaml to add newton-10.0 release.
Impact:
 Non-intuitive method to provide example plugins.
Description of the environment:
 Operation system: <put your information here>
 Versions of components: <put your information here>
 Reference architecture: <put your information here>
 Network model: <put your information here>
 Related projects installed: <put your information here>
Additional information:
 There was a thread on openstack-dev that claimed we should NOT maintain release-to-release compatibility, but a proper solution is yet to be defined.