move attributes of v3.client.Client into alphabetical order

Just make self.users be consistent with the other assignments.

Change-Id: Ib3053774e9dd905eb4ef50668d6638ce19750177
Mark auth plugin options as secret

By marking the options as secret they don't get printed out in things
like the debug log when loading the application.

Change-Id: Iadab479a896bc4b1682ee8d207cc50a01dca8255
Merge "move attributes of v3.client.Client into alphabetical order"
Merge "Mark auth plugin options as secret"