new search popup shows old search term

[samanthasunne]

This is similar to #118 but is a different issue. If the user searches using the search in the nav menu, and then reopens the search popup to search for something else, the old search term still appears in the search popup. It should be blank for the user to do a new search.

In the example below, I searched for "Test 3", looked at the results, opened the nav menu search again, and "Test 3" still appeared where I would type the new search term.

Similar to #118, if this is labor heavy on the webdev side I might be willing to drop it since it's a pretty minor issue.