[krbdev.mit.edu #3929] support lazy launching of ccapi server

[Jeffrey Altman via RT]

On the MacOS X platform the ccapi server will be implemented on a per
session basis.  The server should not be started in response to a
cc_initialize() call.  If the server is not present, the client should
respond with appropriate answers until such time as a cache is to be
created or the server has been started by someone else.  

To support this the cci_perform_rpc() call should take a parameter that
indicates whether starting the server is permitted or not.