Update utils.js (fix TypeError: filterWrapper is not iterable)

[TheTechromancer]

Fix TypeError: filterWrapper is not iterable

Fixes https://github.com/TimeForANinja/node-ytsr/issues/180, https://github.com/codetheweb/muse/issues/948

[nukeop]

This isn't going to help since the search list will simply be empty. So it technically solves the problem with the undefined variable but the search still fails.

[TheTechromancer]

I'm not sure exactly why, but in my testing this change made a big difference. Before, even searching for a very common song (such as grimes realiti) would throw the error and fail to play. But the exact same query with the fix would succeed.

[TimeForANinja]

closing in favor of #203