MdeModulePkg: Add unload support for SnpDxe and fix NULL ImageHandle in EfiLibInstallDriverBindingComponentName2() in driver entry point.

Signed-off-by: xdu2
Reviewed-by: vanjeff

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11967 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/Network/SnpDxe/SnpDxe.inf

@@ -1,7 +1,7 @@
 ## @file
 #    Component description file for SNP module.
 #
-# Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
+# Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
 # This program and the accompanying materials are licensed 
 # and made available under the terms and conditions of the BSD License which 
 # accompanies this distribution. The full text of the license may be found at 
@@ -19,6 +19,7 @@
   MODULE_TYPE                    = UEFI_DRIVER
   VERSION_STRING                 = 1.0
   ENTRY_POINT                    = InitializeSnpNiiDriver
+  UNLOAD_IMAGE                   = NetLibDefaultUnload
 
 #
 # The following information is for reference only and not required by the build tools.
@@ -63,7 +64,7 @@
   UefiDriverEntryPoint
   BaseMemoryLib
   DebugLib
-
+  NetLib
 
 [Guids]
   gEfiEventExitBootServicesGuid                 ## CONSUMES