It could happen that there is "something" streaming from the current primary node with `application_name` that matches name of the current primary, for instance due to a faulty configuration. When processing `pg_stat_replication` we only checked that the `application_name` matches with the name one of the member nodes, but we forgot to exclude our own name.
As a result there were following side-effects:
1. The current primary could be declared as a synchronous node.
2. As a result of [1] it wasn't possible to do a switchover.
3. During shutdown the current primary was waiting for itself to release it from synchronous nodes.
Close#3111
