[Tests] Fix failing tracker_icons test

Disable the testing with seo.com as the site certificate has expired.

Ideally should not be testing against live sites and instead use request
replay tool such as VCR.py.

deluge/tests/test_tracker_icons.py

@@ -8,6 +8,7 @@
 from __future__ import unicode_literals
 
 import pytest
+from twisted.trial.unittest import SkipTest
 
 import deluge.component as component
 import deluge.ui.tracker_icons
@@ -63,6 +64,7 @@ class TrackerIconsTestCase(BaseTestCase):
 
     def test_get_seo_ico_with_sni(self):
         # seo using certificates with SNI support only
+        raise SkipTest('Site certificate expired')
         icon = TrackerIcon(common.get_test_data_file('seo.ico'))
         d = self.icons.fetch('www.seo.com')
         d.addCallback(self.assertNotIdentical, None)