"extractUserPropertyMigrations" Process Exclude Username with Uppercase

Confluence 5.5 upgrade task include migrating user properties with the following SQL queries according to Confluence source code:

select p.entity_name, p.entity_key, u.user_key " +
                            "from OS_PROPERTYENTRY p left join user_mapping u " +
                            "on " + sqlSubstring("p.entity_name", OLD_ENTITY_NAME_PREFIX) + " = u.lower_username " +
                            "where entity_name like ? and entity_id=?

The above SQL queries indicate that Confluence does not migrate users with upper case since OS_PROPERTYENTRY table use username as the identifier instead of lower username.

Since we do support username with uppercase for external users we should use user_name instead of lower_username.