Ticket #47623 fix memleak caused by 47347
    
    https://fedorahosted.org/389/ticket/47623
    Reviewed by: nhosoi (Thanks!)
    Branch: 389-ds-base-1.3.1
    Fix Description: Only need to create the mutex when creating a new PR object.
    Platforms tested: RHEL6 x86_64
    Flag Day: no
    Doc impact: no
    (cherry picked from commit 98ccb602058270e97a3702ae2b81c17635af8d27)
    (cherry picked from commit 65c51555c0ecc94c5d93f09124168697ba1db6b3)
    (cherry picked from commit 8a2c666df491b7c8666f8a70a5038b35c43fbc3b)