LDAP fix

There is a fix (http://jira.xwiki.org/jira/secure/attachment/11161/LDAPAuthServiceImpl-r3342...) for http://jira.xwiki.org/jira/browse/XWIKI-238 (1.0 r 3342) to let a user with mixed case username in LDAP login with all lower case. I do not see how to attach file to this so I attached the patch to http://jira.xwiki.org/jira/browse/XWIKI-238. I have tested by adding a DB user both before and after deploying the change. Regards, Dennis