[6.0] 988baa400 vmodtool: fix object destructor signature

[Dridi Boukelmoune]

commit 988baa400e954ccfd3c2a2304e89ee3affd24004
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Fri Apr 27 16:58:01 2018 +0200

    vmodtool: fix object destructor signature
    
    ... when the constructor has optional arguments

diff --git a/lib/libvcc/vmodtool.py b/lib/libvcc/vmodtool.py
index b4de6a036..8937aefac 100755
--- a/lib/libvcc/vmodtool.py
+++ b/lib/libvcc/vmodtool.py
@@ -719,6 +719,7 @@ class s_object(stanza):
 
         self.fini = copy.copy(self.proto)
         self.fini.name += '__fini'
+        self.fini.argstruct = False
         self.fini.args = []
 
         self.rstlbl = "obj_" + self.proto.name