pglookout: fix fetch_time case when we don't have cluster state for node
pglookout: fix fetch_time case when we don't have cluster state for node

Before this we got a datetime object instead of a ISO timestamp as a string
causing an exception to happen in case we didn't have node state in cluster_state.

Also silence a few log.exceptions to be log.warning

Ormod/pglookout,Ormod/pglookout,saaros/pglookout,ohmu/pglookout