Flushing cache fails to wipe view_preprocessed dir #930
Description
The CSS pre-processing builds everything into the view_preprocessed/source and view_preprocessed/less directories. Even in developer mode and all caches disabled, however, the files in view_preprocessed/less are not updated correctly when changes are made to the theme and the page refreshed (those in view_preprocessed/source are though). This causes even bigger problems because when flushing the cache storage (or cleaning all types) from either the admin or the CLI, these directories are not emptied, resulting in a stale cache which must be manually removed from the file-system to update what's run through the LESS compiler.