Properly close token in sspi authentication

We can never leak more than one token, but we shouldn't do that. We
don't bother closing it in the error paths since the process will
exit shortly anyway.

Christian Ullrich

src/backend/libpq/auth.c

@@ -1255,6 +1255,8 @@ pg_SSPI_recvauth(Port *port)
 				(errmsg_internal("could not get user token: error code %lu",
 								 GetLastError())));
 
+	CloseHandle(token);
+
 	if (!LookupAccountSid(NULL, tokenuser->User.Sid, accountname, &accountnamesize,
 						  domainname, &domainnamesize, &accountnameuse))
 		ereport(ERROR,