Range selector reset, visual fix.

When clearing values for a datepicker range, it does not clear the previous selection causing a visual UX error due to code in getClassNames (line #553). See screenshot @ https://www.evernote.com/shard/s310/sh/d9dcefca-8441-4837-a6ea-257150432bab/cb05fb7bbb84a42732df4f02976e8657. Adding the committed line of code solves this issue.