Kill all tasks on shutdown and startup

BindsTo will kill all the tasks when systemctl stop box is executed.
But when restarted, it keeps the tasks running. Because of this behavior,
we kill the tasks on startup and stop of the box code.

src/apptask.js

@@ -1063,6 +1063,8 @@ function run(appId, args, progressCallback, callback) {
             return stop(app, args, progressCallback, callback);
         case apps.ISTATE_PENDING_RESTART:
             return restart(app, args, progressCallback, callback);
+        case apps.ISTATE_INSTALLED: // can only happen when we have a bug in our code while testing/development
+            return updateApp(app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null }, callback);
         default:
             debugApp(app, 'apptask launched with invalid command');
             return callback(new BoxError(BoxError.INTERNAL_ERROR, 'Unknown install command in apptask:' + app.installationState));