bluez a2dp - use a sensible write timeout

The 500 msec write timeout is extremely optimistic, a 1000 msec
timeout is closer to reality.
diff --git a/audio/liba2dp.c b/audio/liba2dp.c
index b48b954..4f2dda0 100755
--- a/audio/liba2dp.c
+++ b/audio/liba2dp.c
@@ -86,7 +86,7 @@
 #define POLL_TIMEOUT			1000
 
 /* timeout in milliseconds for a2dp_write */
-#define WRITE_TIMEOUT			500
+#define WRITE_TIMEOUT			1000
 
 
 typedef enum {