Fix shellcheck warnings (#1003)

* Use double quote to prevent globbing and exit with error in case
  directory doesn't exit in hassos-hook.sh

* echo flags are undefined in POSIX, use bash instead in
  bluetooth-rtl8723

buildroot-external/package/bluetooth-rtl8723/bluetooth-rtl8723

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 echo "Setup the Bluetooth chip"
 echo 146 > /sys/class/gpio/export