fix the default values for token and password auth

Change-Id: Ie0cd80ce1dcf5186367896e1a84a441dc2e2c72d
Fixes: Bug #1213216
Ensure username passed by REMOTE_USER can contain '@'

The external authentication support allows the domain to be passed
as part of the REMOTE_USER name, by using the '@' as a delineator,
but did not handle the case when the actual username itself also
contained the '@' character.

Fixes bug 1213842

Change-Id: Idffa42fe9c70818c71379669dfcd17d3113738a3
use provider to validate tokens

Validate V2 token when passed to V3 api
Push the validation logic to the provider
token auth plugin works on data from v2 or v3

Bug 1212778

Change-Id: Ib2f77839c907d5013d33660920fa902613be4fb5
Merge "use provider to validate tokens"
Merge "Ensure username passed by REMOTE_USER can contain '@'"
Merge "fix the default values for token and password auth"