replay: Detect errors from red_replay_data_chunks
replay: Detect errors from red_replay_data_chunks

Change the return to ssize_t to be able to distinguish from
empty buffer to error.
Check result returned and avoid continuing potentially
deferencing NULL pointers.

Signed-off-by: Frediano Ziglio <55d48b080b2e443e395cde84d2c83b135a4ff48e@redhat.com>
Acked-by: Jonathon Jongsma <c7254805a17bd5c41e24c3a278fcbf3afcdfb0fa@redhat.com>

fgouget/spice,fgouget/spice,fgouget/spice,fgouget/spice