Use toLocalFile function instead of slicing.

qutebrowser/browser/webpage.py

@@ -161,7 +161,7 @@ class BrowserPage(QWebPage):
                     return False
             elif (error_str.endswith('Path is a directory') and
                   info.url.scheme() == 'file'):
-                html = dirbrowser(info.url.url()[7:])
+                html = dirbrowser(info.url.toLocalFile())
                 errpage.content = html.encode('utf-8')
                 errpage.encoding = 'utf-8'
                 return True

tests/browser/test_dirbrowser.py

@@ -36,7 +36,6 @@ class TestFileList:
         assert {'name': 'testfile', 'absname': os.path.join(basedir,
                 'testfile')} in result
 
-        """Test get_file_list with os.path.isdir filter function."""
         basedir = os.path.abspath('./qutebrowser/utils')
         all_files = os.listdir(basedir)
         result = get_file_list(basedir, all_files, os.path.isdir)