bluez: Install gatttool for Bluetooth Low Energy

gatttool is not included in `make install`. The Debian package
similarly copies it out of the build directory.

Signed-off-by: Kevin Mehall <km@kevinmehall.net>

utils/bluez/Makefile

@@ -111,6 +111,7 @@ define Package/bluez-utils/install
 	$(CP) $(PKG_INSTALL_DIR)/usr/bin/* $(1)/usr/bin/
 	$(CP) $(PKG_INSTALL_DIR)/usr/lib/bluetooth/bluetoothd $(1)/usr/bin/
 	$(CP) $(PKG_INSTALL_DIR)/usr/lib/bluetooth/obexd $(1)/usr/bin/
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/attrib/gatttool $(1)/usr/bin/
 	$(INSTALL_DIR) $(1)/etc/config
 	$(INSTALL_DATA) ./files/bluetooth.config $(1)/etc/config/bluetooth
 	$(INSTALL_DIR) $(1)/etc/dbus-1/system.d/