Bug 617630 - fix coverify Defect Type: Resource leaks issues CID 12052 - 12093

https://bugzilla.redhat.com/show_bug.cgi?id=617630
Resolves: bug 617630
Bug description: fix coverify Defect Type: Resource leaks issues CID 12067
description: usn_cleanup_add() has been modified to release unused resource when error occurs.

ldap/servers/plugins/usn/usn_cleanup.c

@@ -302,6 +302,7 @@ usn_cleanup_add(Slapi_PBlock *pb, Slapi_Entry *e, Slapi_Entry *eAfter,
             "USN tombstone cleanup: unable to allocate new task.\n");
         *returncode = LDAP_OPERATIONS_ERROR;
         rv = SLAPI_DSE_CALLBACK_ERROR;
+        slapi_ch_free((void**)&cleanup_data);
         goto bail;
     }