Implement get SD card status (if it's mounted or not).

lib/roles/device/plugins/service.js

@@ -565,6 +565,21 @@ module.exports = syrup.serial()
       })
     }
 
+    plugin.getSdStatus = function () {
+      return runServiceCommand(
+        apk.wire.MessageType.GET_SD_STATUS
+      , new apk.wire.GetSdStatusRequest()
+      )
+      .timeout(10000)
+      .then(function(data) {
+        var response = apk.wire.GetSdStatusResponse.decode(data)
+        if (response.success) {
+          return response.mounted
+        }
+        throw new Error('Unable to get SD card status')
+      })
+    }
+
     plugin.pressKey = function(key) {
       keyEvent({event: apk.wire.KeyEvent.PRESS, keyCode: keyutil.namedKey(key)})
       return Promise.resolve(true)