SERVER-9516 Remove dead code from auth_index_d module.
SERVER-9516 Change schema upgrade interface in AuthorizationManager.

Update the unit tests to reflect the new interface, and various other
changes that occurred while some tests were disabled.
SERVER-9516 Remove unused methods from AuthzManagerExternalState.
SERVER-9516 Factor out common code from mock & mongod implementations of AuthzManagerExternalState.
SERVER-9516 Remove canDelegate and hasRole from auth docs in unit test.