There are now too many options to sensibly fit into general --help
output; we'll add separate output for each repmgr command, e.g.
"repmgr node --help".
If the current primary (demotion candidate) still has any files to archive,
it will delay the shutdown until all files are archived. If there is a
substantial number of files, and/or the archive command executes slowly,
this will probably lead to an unwelcome delay in the switchover process.
This is needed for better switchover control, so we can instruct
the remote repmgr to issue the appropriate server command rather
than trying to work out what it should be from the local node.
