Start both v1 and v2 api from one daemon.

- Move bin/ceilometer-api-v2 to bin/ceilometer-api
- use VersionSelectorApplication() as the base application.

bug #1086381
Change-Id: Ia74938eb351fc374450932a91b21c0755afca2e5
Signed-off-by: Angus Salkeld <asalkeld@redhat.com>
Merge "Start both v1 and v2 api from one daemon."