r2458: Rename policy handle parameters for the SAMR pipe. Parameters now

r2458: Rename policy handle parameters for the SAMR pipe.  Parameters now
have the handle type implied by the parameter name.  There are four
types of handle: connect, domain, user and group handles.  The
various samr_Connect functions return a connect handle, and the
samr_OpenFoo functions return a foo handle.

There is one exception - the samr_{Get,Set}Security function can
take any type of handle.

Fix up all C callers.
(This used to be commit 32f0f3154a8eb63de83145cbc8806b8906ccdc3e)