Rename attribute of GET /flavors response, from 'cpu' to 'vcpus'.
Catholicaly remove "values" term from requests and responses
cyclades: Rename meta to metadata at Cyclades URLs:
    * /servers/<server-id>/meta
    * /servers/<server-id>/meta/<key>
    * /images/<image-id>/meta
    * /images/<image-id>/meta/<key>

Refs: #3768