FIX: Don’t raise on some search terms

Currently, when certain search terms are provided, this can lead to
`Search.need_segmenting?` raising an error because it makes `URI#path`
to return `nil` instead of a string.

This patch forces a cast to string so it won’t raise anymore.

lib/search.rb

@@ -228,7 +228,7 @@ class Search
 
   def self.need_segmenting?(data)
     return false if data.match?(/\A\d+\z/)
-    !URI.parse(data).path.start_with?("/")
+    !URI.parse(data).path.to_s.start_with?("/")
   rescue URI::InvalidURIError
     true
   end