Work-around (not really a fix) by keeping local 'require' (bug 1036381)

Work around to prevent getting undefined `require` until we figure out a better long-term fix for the problem that caused us to set require to undefined in the first place (see 
https://github.com/mozilla/zamboni/blob/master/media/js/lib/diff_match_patch_uncompressed.js#L22 )