Fix another place clang complains about

Fix another place clang complains about.

Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Nigel Croxon <ncroxon@redhat.com>

lib/guid.c

@@ -97,7 +97,7 @@ static struct {
 	{  &SMapId,                                         L"ShellDevPathMap" },
 	{  &SAliasId,                                       L"ShellAlias" },
 
-	{  NULL, NULL }
+	{  NULL, L"" }
 };
 
 //