Now in API reference, variable name `member_of` is used for
`GET /resource_providers` doc and `member_of_1_12` is used for
`GET /allocation_candidate` doc. However, since we also have
`member_of_granular` this can be confusing.
This patch renames as follows:
- `member_of` -> `resource_providers_member_of`
- `member_of_1_12` -> `allocation_candidates_member_of`
- `member_of_granular` -> `allocation_candidates_member_of_granular`
No content is changed.
Change-Id: I3a8591d9ed76eed60e11d59cff77cfbf95796478