[mod_dptools] scan-build: Fix "Potential leak of memory pointed to by 'head'"

src/mod/applications/mod_dptools/mod_dptools.c

@@ -3868,7 +3868,7 @@ static void pickup_add_session(switch_core_session_t *session, const char *key)
 		key = dup_key;
 	}
 
-	node = malloc(sizeof(*node));
+	switch_zmalloc(node, sizeof(*node));
 	switch_assert(node);
 	node->key = strdup(key);
 	node->uuid = strdup(switch_core_session_get_uuid(session));