audiohook.c: resolving the issue with audiohook both reading when packet loss on...

audiohook.c: resolving the issue with audiohook both reading when packet loss on one side of the call

When there is 0% packet loss on one side of the call and 15% packet loss on the other side, reading frame is often failed when reading direction_both audiohook. when read_factory available = 0, write_factory available = 320; i think write factory is usable read; because after reading one frame, there is still another frame that can be read together with the next read factory frame.

Resolves: #851