[SPOOLSS]

[SPOOLSS]
Rewrite RevertToPrinterSelf and ImpersonatePrinterClient.
In contrast to what I first thought, they shall also work when the thread has no impersonation token. This occurs for example when spooler functions are called from a thread that doesn't originate from a RPC request.
The rewritten functions also provide proper error codes.

The native behaviour of these functions was verified through API Monitoring under Windows.

svn path=/branches/colins-printing-for-freedom/; revision=68472