[krbdev.mit.edu #3932] CCAPI should use a cc_handle not implemented as a pointer

[Jeffrey Altman via RT]

The cc_handle is currently a 64-bit unsigned integer however its value
is obtained by casting a pointer.  The forward and reverse casts may not
be safe on all platforms and often produce many warnings.  Implementing
casting functions is a possibility.  However, if it is not more work a
better scheme would be to use an index value that looks up the
appropriate pointer in a table.