For profile name, enhance win32 heuristics to use environment variable

For profile name, enhance win32 heuristics to use environment variable
(like Unix) and registry.  Also try executable's dir before windows dir
if not secure.

For ccname, enhance win32 heuristics to use registry properly.  Default
to API:krb5cc properly, and to use temp dirs before the windows dir.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@11516 dc483132-0cff-0310-8789-dd5450dbe970