drop unused setDefault, ignore error handler coverage

Signed-off-by: Jakub Sokołowski <jakub@status.im>

src/app.js

@@ -11,6 +11,7 @@ const App = ({ghc, schema}) => {
   const router = new JoiRouter()
 
   app.on('error', (err, ctx) => {
+    /* istanbul ignore next */
     console.error('server error', err, ctx)
   })
 

src/utils.js

@@ -16,8 +16,4 @@ const extractArchiveBuilds = (builds) => {
   return {visible, archived}
 }
 
-const setDefault = (obj, prop, deflt) => {
-  return obj.hasOwnProperty(prop) ? obj[prop] : (obj[prop] = deflt);
-}
-
-module.exports = { extractArchiveBuilds, setDefault }
+module.exports = { extractArchiveBuilds }