Revision 1265

Recover missing 4 bytes in audio-stream thanks to a hint in an old
email from Robert Sanders <esquimaux73@mailblocks.com>:

I found a trick that seems to solve this.  Basically, I copy the last
4 bytes of the RDPSND_WRITE command that precedes the sample data.
It's not being used by anything else.  I can't tell whether this is
some trick to "pre-load" the sample buffer, or some error in
rdesktop's interpretation of the RDP sound protocol.