[#4] Make use of fence_intervals config

pvcd/NodeInstance.py

@@ -251,7 +251,7 @@ class NodeInstance():
             # Handle deadtime and fencng if needed
             # (A node is considered dead when its keepalive timer is >6*keepalive_interval seconds
             # out-of-date while in 'start' state)
-            node_deadtime = int(time.time()) - ( int(self.config['keepalive_interval']) * 6 )
+            node_deadtime = int(time.time()) - ( int(self.config['keepalive_interval']) * int(self.config['fence_intervals']) )
             if node_keepalive < node_deadtime and node_daemon_state == 'run':
                 # CHECK VERSIONING HERE
                 ansiiprint.echo('Node {} seems dead - starting monitor for fencing'.format(node_name), '', 'w')