am 2a8c49eb: fix an out-of-bounds memory access

                     * the consumer may still have pending reads of the

                     * buffers in flight.

                     */

                    if (found >= 0) {

                        bool isOlder = mSlots[i].mFrameNumber <

                                mSlots[found].mFrameNumber;

                    if (found < 0 || isOlder) {

                        if (isOlder) {

                            found = i;

                        }

                    }

                }

            }

            // clients are not allowed to dequeue more than one buffer

            // if they didn't set a buffer count.