namespaces: zero struct ns_id when allocating

Later (find_ext_ns_id, but probably others as well) we depend on the struct
being zeroed in order to figure out whether or not to collect info about
it. Let's make sure it is actually zeroed.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/namespaces.c

@@ -259,7 +259,7 @@ static unsigned int generate_ns_id(int pid, unsigned int kid, struct ns_desc *nd
 	} else
 		type = NS_CRIU;
 
-	nsid = xmalloc(sizeof(*nsid));
+	nsid = xzalloc(sizeof(*nsid));
 	if (!nsid)
 		return 0;