EAuthenticationMediator: Fix some runtime warnings.
EAuthenticationMediator: Fix some runtime warnings.

In authentication_mediator_authenticator_thread(), the GDBusInterface
was getting finalized a bit too soon.

Distrotech/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,Distrotech/evolution-data-server,Distrotech/evolution-data-server,Distrotech/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,Distrotech/evolution-data-server