open() hang if it failed to load URL

[vlet]

For example

$webkit = WWW::WebKit->new(xvfb => 1);
$webkit->init;
$webkit->open("https://notexists.domain"); # hang there forever

This patch seems to fix problem, but looks ugly:

 sub open {
    my ($self, $url) = @_;
    $self->view->open($url);

-    Gtk3::main_iteration while Gtk3::events_pending or $self->view->get_load_status ne 'finished';
+    Gtk3::main_iteration
+      while Gtk3::events_pending
+      or !($self->view->get_load_status eq 'finished'
+        || $self->view->get_load_status eq 'failed' );
 }