Ticket 49379 - Allowed sasl mapping requires restart
    
    Bug Description:  If allowed sasl mechanisms are configured, and the server is
                      restarted, trying to add new sasl mechanisms does not get applied
                      until the server is restarted again. [1]
    
                      We were also overwriting memory when we stripped the commas from
                      the allowed machanism list.  THis lead to the allowed mechanisms
                      to get truncated,and permanently lose certain mechs. [2]
    
                      A crash with PLAIN sasl mechanism was also found. [3]
    
    Fix Description:  To address allowed sasl mechs, we no longer explicitly the mechanisms
                      during the sasl_init at server startup.  Instead we check the allowed
                      list ourselves during a bind. [1]
    
                      When setting the allowed sasl mechs, make a copy of the value to
                      apply the changes to(removing coamms), and do not change the original
                      value as it's still being used. [2]
    
                      The crash when using sasl PLAIN was due to unlocking a rwlock that
                      was not locked. [3]
    
    https://pagure.io/389-ds-base/issue/49379
    
    Reviewed by: tbordaz(Thanks!)
    
    (cherry picked from commit c78f41db31752a99aadd6abcbf7a1d852a8e7931)