- Fixed bug which prevented MySQLdb-based dialects (e.g.

- Fixed bug which prevented MySQLdb-based dialects (e.g.
pymysql) from working in Py3K, where a check for "connection
charset" would fail due to Py3K's more strict value comparison
rules.  The call in question  wasn't taking the database
version into account in any case as the server version was
still None at that point, so the method overall has been
simplified to rely upon connection.character_set_name().
[ticket:2933]