NetworkPkg:Fix Network memory leak when calling GetModeData interface

Multiple network protocols have a GetModeData() interface, which may
allocate memory resource in the return mode data structure. It's
callers responsibility to free these buffers.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Zhang Lubo <lubo.zhang@intel.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19758 6f19259b-4bc3-4df7-8a09-765794883524

NetworkPkg/Dhcp6Dxe/ComponentName.c

@@ -1,7 +1,7 @@
 /** @file
   UEFI Component Name(2) protocol implementation for Dhcp6 driver.
 
-  Copyright (c) 2009 - 2014, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2009 - 2016, 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
@@ -286,7 +286,14 @@ UpdateName (
     }
     HandleName = mDhcp6ControllerName[Dhcp6ModeData.Ia->State];
   }
-  
+
+  if (Dhcp6ModeData.Ia != NULL) {
+    FreePool (Dhcp6ModeData.Ia);
+  }
+  if (Dhcp6ModeData.ClientId != NULL) {
+    FreePool (Dhcp6ModeData.ClientId);
+  }
+
   Status = AddUnicodeString2 (
              "eng",
              gDhcp6ComponentName.SupportedLanguages,