Report merging snapshot as 'S' instead of 's':

Report merging snapshot as 'S' instead of 's':
This is useful for when the snapshot is still active and merging hasn't
started yet; it shows a merge is pending.  Once merging starts the
merging snapshot will be hidden but can still be displayed with 'lvs -a'

Report snapshot origin with merging snapshot as 'O' instead of 'o':
Before merge starts this shows that a merge is pending.  While merging
the snapshot will be hidden, 'O' enables a user to see that there is a
snapshot merging.