sleep (in thread) before closing proxy socket. This works around

problem where, on PRX_HAS_MSGS path only, device reading socket gets
EOF early though logging here confirms additional bytes have been
written.  Gross but effective.

xwords4/relay/xwrelay.cpp

@@ -750,6 +750,7 @@ handle_proxy_tproc( void* closure )
             }
         }
     }
+    sleep( 2 );
     close( sock );
     return NULL;
 } /* handle_proxy_tproc */