Fixes modernizr not being enqueued

https://github.com/roots/roots/issues/1223
https://github.com/roots/roots/issues/1223#issuecomment-65754009
Merge pull request #1224 from austinpray/gulp

Fixes modernizr not being enqueued
Merge remote-tracking branch 'upstream/gulp' into gulp

* upstream/gulp:
  Fixes modernizr not being enqueued