Log: fencing: rename fence action IDs

Previously, fence action IDs were named like AGENT_ACTION_ATTEMPT, for example
fence_dummy_monitor_1. This was easily confused (in logs) with normal resource
actions where the last number is the interval.

To make the distinction clearer, name them like
AGENT_ACTION_ATTEMPTofMAXATTEMPTS, for example fence_dummy_monitor_1of2.