retrieve mw version from live wiki for APISite class

- override family method version() for APISite class
- log site.version() which is live version
- remove obsolete version() from WikimediaFamily class because
  we use APISite for all wikimedia families and we get the
  version information from live wiki
- declare live_version() as deprecated
- test site.version() instead of deprecated live_version()

Change-Id: Icd1c972d5d2deffc60dd78ec3f63b64318ed2d06