cluster: fix typo in maxStandbyLag json field name
cluster: fix typo in maxStandbyLag json field name

maxStandbyLage => maxStandbyLag

sgotti/stolon,sgotti/stolon,sorintlab/stolon,sorintlab/stolon,siepkes/stolon,siepkes/stolon,smkingsoft/stolon,smkingsoft/stolon