Ticket #47623 fix memleak caused by 47347
https://fedorahosted.org/389/ticket/47623
Reviewed by: tbordaz, nhosoi (Thanks!)
Branch: 389-ds-base-1.3.2
Fix Description: Create the mutex if it doesn't exist.
Platforms tested: RHEL6 x86_64
Flag Day: no
Doc impact: no
(cherry picked from commit 0d4849dd7551347f0e24ac1027f4d0501084dcf3)