Merge of r4933, r4933: shared memory fixes. *) Fixed location of debug message in ngx_shmtx_lock(). *) Core: don't reuse shared memory zone that changed ownership (ticket #210). nginx doesn't allow the same shared memory zone to be used for different purposes, but failed to check this on reconfiguration. If a shared memory zone was used for another purpose in the new configuration, nginx attempted to reuse it and crashed.