fix(cursor): call `initialize` after session support check
fix(cursor): call `initialize` after session support check

If a cursor needed to check for session support it would do so, and
then call the `next` function which in most cases would directly
call `_initialize` again - but sometimes would erroneously issue
a `getMore`.

mongodb/node-mongodb-native,mongodb/node-mongodb-native,mongodb/node-mongodb-native,mongodb/node-mongodb-native