[BRLTTY] auth server refuses to start if built without polkit

[Chris Brannon]

In Programs/brlapi.h.in, we have:
#define BRLAPI_DEFAUTH "polkit+keyfile:" BRLAPI_ETCDIR "/" BRLAPI_AUTHKEYFILE
This is the default, even when polkit support is not built.
The initializeMethodDescriptors code from Programs/auth.c is very
simple.  If any method descriptor fails to initialize, then all of them
are released, and the auth server will not start.
The polkit method descriptor cannot be initialized, because polkit
support was not built, so the auth server cannot start with this value
of BRLAPI_DEFAUTH.  Seems like this would be fixed with a pretty simple
change to Programs/brlapi.h.in.  I can send a patch if you like.

-- Chris