auth_context flag for sending AP_REQ

[Ken Hornstein]

I was looking at implementing the code Sam and I talked about relating
to directional address types, and I noticed the following definitions
in auth_con.h:

#define KRB5_AUTH_CONN_USED_W_MK_REQ    0x00020000
#define KRB5_AUTH_CONN_USED_W_RD_REQ    0x00040000

Perusing the CVS logs, they've been around for a long time (since the first
commit of that file, apparantly), but I can't find that they're used for
anything.  Should I co-op these definitions (they're vaguely named for
what I want), or should I create a new internal flag for setting whether
or not a implementation has issued an AP_REQ?  (I'm leaning toward the
latter, but I just thought I'd bring this stuff up).

--Ken