Fix search unnecessarily requiring source files

This seems to have been a mistake with #4022 the ajax call functions correctly without the source files being included in the build (they are never used).

I have tested this out on several themes and now everything works correctly with `html_copy_source = False`

sphinx/themes/basic/static/searchtools.js

@@ -276,7 +276,7 @@ var Search = {
           setTimeout(function() {
             displayNextItem();
           }, 5);
-        } else if (DOCUMENTATION_OPTIONS.HAS_SOURCE) {
+        } else {
           $.ajax({url: requestUrl,
                   dataType: "text",
                   complete: function(jqxhr, textstatus) {
@@ -289,12 +289,6 @@ var Search = {
                       displayNextItem();
                     }, 5);
                   }});
-        } else {
-          // no source available, just display title
-          Search.output.append(listItem);
-          setTimeout(function() {
-            displayNextItem();
-          }, 5);
         }
       }
       // search finished, update title and status message