MdeModulePkg/NetworkPkg: Checking for NULL pointer before use.

Contributed-under: TianoCore Contribution Agreement 1.1

Signed-off-by: Sivaraman Nainar <sivaramann@amiindia.co.in>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>

NetworkPkg/IpSecDxe/Ikev2/Utility.c

@@ -2438,7 +2438,7 @@ Ikev2ChildSaParseSaPayload (
   IntegrityAlgorithm       = 0;
   EncryptAlgorithm         = 0;
   EncryptKeylength         = 0;
-  IsMatch                  = TRUE;
+  IsMatch                  = FALSE;
   IsSupportEsn             = FALSE;
   PreferIsSupportEsn       = FALSE;