If external link inserted with link wizard, empty input

Fixes #1483

lib/scripts/linkwiz.js

@@ -259,7 +259,14 @@ var dw_linkwiz = {
         dw_linkwiz.hide();
 
         // reset the entry to the parent namespace
-        dw_linkwiz.$entry.val(dw_linkwiz.$entry.val().replace(/[^:]*$/, ''));
+        var externallinkpattern = new RegExp('^((f|ht)tps?:)?//', 'i'),
+            entry_value;
+        if(externallinkpattern.test(dw_linkwiz.$entry.val())) {
+            entry_value = ''; //reset whole external links
+        }else {
+            entry_value = dw_linkwiz.$entry.val().replace(/[^:]*$/, '')
+        }
+        dw_linkwiz.$entry.val(entry_value);
     },
 
     /**