For those people who insist on ignoring the obvious.

Missed this in 7ce29b9e

Hallvard Furuseth authored Jul 11, 2015 and Howard Chu committed Jul 28, 2015

Except we don't catch the user passing F_SUBDATA to
mdb_cursor_<put/del>, like an internal LMDB call.

Don't change mc_dbx because we would need to undo the change if
the txn aborts. Make the fix (for get) match existing code for put.

This reverts commit 47c4e747.

Revert "ITS#8117 fix INTEGERDUP compare"

This reverts commit ba45e0c0.

Fix mdb_txn_begin(&read-only txn) calls. Test mdb_env_set_maxreaders().
Rename DBI open/close functions. Move mdb_dbi_close() out of txn.