Bug 1038097: Include <errno.h> in BluetoothInterface.cpp, r=shuang

This patch adds a missing include statement for <errno.h> to
BluetoothInterface.cpp. This fixes the build for flatfish
devices. For safety, the patch also adds an include statement
for <unistd.h>, which might be necessary for several functions.

dom/bluetooth/bluedroid/BluetoothInterface.cpp

@@ -4,6 +4,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include <errno.h>
+#include <unistd.h>
 #include <sys/socket.h>
 #include "base/message_loop.h"
 #include "BluetoothInterface.h"