Revert "Merge pull request #76 from tiger-swallowtails-2014/fix-broken-j...

...avascript-on-welcome-page"

This reverts commit 8ea578e113a6a84d7ff7d40a3fc5ea9ad66f7d08, reversing
changes made to aebf180374a27b38e7f04e42a3a9de7592f28205.

This was designed to prevent errors on
welcome#index when the map element was not
present.  It's breaking the /musicians route, so
let's not do that.

The JS error is not fatal on welcome#index