unset() should be used with more caution in views_filter_handler_simple.inc

Hello,

I was working on implementing a form_alter() for a View that had exposed filters (my goal was to remove some of the items from the exposed filter). The exposed filter is displaying dates as Years associated with some nodes. I'm able to alter the form, but when the user tries to select a different year from the exposed filter, there's a "Fatal error: cannot unset string offsets" in date_views/includes/date_views_filter_handler_simple.inc.

The simple fix for this is to check if $element_input is an array before attempting to call unset() on it.