Frank Cusack's patches, first two sets. Should be no incompatible changes,

Frank Cusack's patches, first two sets.  Should be no incompatible changes,
except perhaps for a client talking to both a new and old KDC?  Several
improvements to guard against replay attacks when hardware preauth is in use,
though they require re-enabling the USE_RCACHE code, which I haven't done yet.

Several changes of mine for silencing a few compiler warnings, and adding some
debugging log messages while I track what's going on with the preauth code.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@12010 dc483132-0cff-0310-8789-dd5450dbe970