Include an error description for failed installations.

lib/units/device/plugins/install.js

@@ -10,6 +10,7 @@ var logger = require('../../../util/logger')
 var wire = require('../../../wire')
 var wireutil = require('../../../wire/util')
 var promiseutil = require('../../../util/promiseutil')
+var responseCodes = require('./install/response-codes')
 
 // The error codes are available at https://github.com/android/
 // platform_frameworks_base/blob/master/core/java/android/content/
@@ -179,7 +180,9 @@ module.exports = syrup.serial()
           )
           push.send([
             channel
-          , reply.fail(err.code)
+          , reply.fail(err.code, {
+              description: responseCodes[err.code] || null
+            })
           ])
         })
         .catch(function(err) {