Fix a warning with some compilers about non-initialized variable.
This can't really happen in real execution, but let's be the compiler happy ;)

Modified: trunk/reactos/drivers/dd/serial/pnp.c

--- trunk/reactos/drivers/dd/serial/pnp.c	2005-03-18 17:45:59 UTC (rev 14179)
+++ trunk/reactos/drivers/dd/serial/pnp.c	2005-03-18 19:00:48 UTC (rev 14180)
@@ -19,7 +19,7 @@

 	IN PDEVICE_OBJECT Pdo)
 {
 	PDEVICE_OBJECT Fdo = NULL;

-	PSERIAL_DEVICE_EXTENSION DeviceExtension;

+	PSERIAL_DEVICE_EXTENSION DeviceExtension = NULL;

 	NTSTATUS Status;
 	WCHAR DeviceNameBuffer[32];
 	UNICODE_STRING DeviceName;