pg_upgrade: fix shutdown check for standby servers
Commit
244142d32afd02e7408a2ef1f249b00393983822 only tested for the
pg_controldata output for primary servers, but standby servers have
different "Database cluster state" output, so check for that too.
Diagnosed-by: Michael Paquier
Discussion: https://postgr.es/m/
20180810164240.GM13638@paquier.xyz
Backpatch-through: 9.3