Change api status code from 500 to 200 in order to display error info in page.

lib/units/storage/plugins/apk/index.js

@@ -37,7 +37,7 @@ module.exports = function(options) {
       })
       .catch(function(err) {
         log.error('Unable to read manifest of "%s"', req.params.id, err.stack)
-        res.status(500)
+        res.status(200)
           .json({
             success: false
           })