CRM_Core_DAO::objectExists() broken by MySQL liberal collation rules

CRM_Core_DAO::objectExists() uses DB_DataObject?s find() method to check whether another object with the same properties exists; this is then used by the objectExists rule in, for example, checks for prefix names? duplicacy.

Unfortunately (well, not really?), the MySQL?s collation rules we use (utf8_unicode_ci) is not only case-sensitive, but also collates characters quite liberally (for example, resolving e, é and ? into the same character):

mysql> SELECT * FROM civicrm_individual_prefix WHERE name LIKE 'Sen%';
---------------------------------- | id | domain_id | name | weight | is_active |
----------------------------------

----------------------------------
3 rows in set (0.00 sec)

This can be side-stepped by specifying the binary collation:

mysql> SELECT * FROM civicrm_individual_prefix WHERE name LIKE 'Sen%' COLLATE utf8_bin;
--------------------------------

--------------------------------

--------------------------------
1 row in set (0.00 sec)

This is what should be done by the objectExists() method.

Note: MySQL 4.0 does not support collations, so the code to do the actual select should depend on CIVICRM_MYSQL_VERSION.