corrected error with ldap strateg not mapping uppercased attrs correctly

nickname was not being set by the strategy when uid and userid attrs where not returned by the ldap and when sAMAccountName was returned. This happens when using MS Active Directory. the reason this happened was that when the mapping to user_info was done each of the values in the @@config where downcased. This meant the @@config value of sAMAccountName was changed to samaccountname which is not what AD returns. 

The change I made checks the downcased value first and then attempts using the value as provided in @@config. 

Updated rpsec as well.