make sure log_error_write can never overflow buffer
make sure log_error_write can never overflow buffer

Change-Id: I4f9f46b56cf316fcf66b56932369e657953deef7
Reviewed-on: http://review.northscale.com/1796
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>
Tested-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>

couchbase/moxi,couchbase/moxi,membase/moxi,zbase/moxi,couchbase/moxi,zbase/moxi,membase/moxi,zbase/moxi,steveyen/moxi,steveyen/moxi,membase/moxi,zbase/moxi,membase/moxi,couchbase/moxi,couchbase/moxi,zbase/moxi,couchbase/moxi,membase/moxi,steveyen/moxi,steveyen/moxi,membase/moxi,steveyen/moxi