YoutubeIE: new algo for length 86 (fixes #1156)

Now is using the same length as the flash player used for age protected videos, but the algorithm is different, so now for age protected videos it first tries to use the old algo.

test/test_youtube_sig.py

@@ -10,7 +10,9 @@ sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 from youtube_dl.extractor.youtube import YoutubeIE
 from helper import FakeYDL
 
-sig = YoutubeIE(FakeYDL())._decrypt_signature
+ie = YoutubeIE(FakeYDL())
+sig = ie._decrypt_signature
+sig_age_gate = ie._decrypt_signature_age_gate
 
 class TestYoutubeSig(unittest.TestCase):
     def test_92(self):
@@ -35,7 +37,7 @@ class TestYoutubeSig(unittest.TestCase):
 
     def test_86(self):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|};?/>.<"
-        right = "ertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!/#$%^&*()_-+={[|};?@"
+        right = ">.1}|[{=+-_)(*&^%$#@!MNBVCXZASDFGHJK<POIUYTREW509876L432/mnbvcxzasdfghjklpoiuytre"
         self.assertEqual(sig(wrong), right)
 
     def test_85(self):
@@ -67,6 +69,11 @@ class TestYoutubeSig(unittest.TestCase):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKHGFDSAZXCVBNM!@#$%^&*(-+={[};?/"
         right = "Z?;}[{=+-(*&^%$#@!MNBVCXRASDFGHKLPOIUYT/EWQ0q87659321mnbvcxzasdfghjkl4oiuytrewp"
         self.assertEqual(sig(wrong), right)
+    
+    def test_86_age_gate(self):
+        wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|};?/>.<"
+        right = "ertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!/#$%^&*()_-+={[|};?@"
+        self.assertEqual(sig_age_gate(wrong), right)
 
 if __name__ == '__main__':
     unittest.main()