lowerOpen / upperOpen were being interpreted incorrectly

Querying with an IDBKeyrange.only() range would fail because the SQL statement issued would contain something like:

"WHERE propertyName NOT NULL AND propertyName > ? AND propertyName < ? ..."

instead of

"WHERE propertyName NOT NULL AND propertyName >= ? AND propertyName <= ? ..."

I fixed the 2 lines where you interpret lowerOpen and upperOpen