pg_rewind is not part of the core distribution for those, but we
provided support in repmgr 3.3 so should extend it to repmgr 4.
Note that there is no check in place whether the pg_rewind binary
exists, so it's up to the user to ensure it's present.
Addresses GitHub #413.
During a switchover operation, once the demoted primary has been restarted
as a standby, repmgr attempts to reconnect to verify its status and drop
any redundant replication slots. However it's possible the standby may still
be in the startup phase, so poll for "standby_reconnect_timeout" seconds
before giving up.
Addresses GitHub #408.
Previously, if an issue was encountered with the old primary, but user
provided -F/--force to have repmgr promote the standby anyway, repmgr
would exit with the log message "STANDBY SWITCHOVER is complete"
and exit code 0 (SUCCESS).
To better report this partial completion, repmgr will now emit the message
"STANDBY SWITCHOVER has completed with issues" (and a HINT to check preceding
log messages) and new exit code 22 (ERR_SWITCHOVER_INCOMPLETE).
