Fix shell output.

lib/roles/device/plugins/shell.js

@@ -42,7 +42,7 @@ module.exports = syrup.serial()
           function endListener() {
             push.send([
               channel
-            , reply.okay()
+            , reply.okay(null)
             ])
             resolver.resolve()
           }
@@ -55,6 +55,8 @@ module.exports = syrup.serial()
             stream.end()
           }
 
+          stream.setEncoding('utf8')
+
           stream.on('readable', readableListener)
           stream.on('end', endListener)
           stream.on('error', errorListener)