Bug 1282839 - Make CustomWhiteNoise easier to understand
Bug 1282839 - Make CustomWhiteNoise easier to understand

The existing behaviour in `update_files_dictionary()` wasn't as obvious
as it could be. This is a no-op in terms of functionality.

glenn124f/treeherder,edmorley/treeherder,tojonmz/treeherder,akhileshpillai/treeherder,kapy2010/treeherder,glenn124f/treeherder,tojonmz/treeherder,edmorley/treeherder,tojon/treeherder,KWierso/treeherder,akhileshpillai/treeherder,akhileshpillai/treeherder,KWierso/treeherder,edmorley/treeherder,kapy2010/treeherder,tojon/treeherder,tojonmz/treeherder,edmorley/treeherder,glenn124f/treeherder,tojonmz/treeherder,kapy2010/treeherder,KWierso/treeherder,tojonmz/treeherder,KWierso/treeherder,akhileshpillai/treeherder,kapy2010/treeherder,glenn124f/treeherder,tojon/treeherder,akhileshpillai/treeherder,glenn124f/treeherder,akhileshpillai/treeherder,tojonmz/treeherder,glenn124f/treeherder,kapy2010/treeherder,tojon/treeherder