[mod] webutils.py: remove dead code

secret_key can't be bytes (see settings_default.py)

searx/webutils.py

@@ -77,14 +77,7 @@ def get_result_templates(templates_path):
 
 
 def new_hmac(secret_key, url):
-    try:
-        secret_key_bytes = bytes(secret_key, 'utf-8')
-    except TypeError as err:
-        if isinstance(secret_key, bytes):
-            secret_key_bytes = secret_key
-        else:
-            raise err
-    return hmac.new(secret_key_bytes, url, hashlib.sha256).hexdigest()
+    return hmac.new(secret_key.encode(), url, hashlib.sha256).hexdigest()
 
 
 def prettify_url(url, max_length=74):

tests/unit/test_webutils.py

@@ -78,10 +78,12 @@ class TestUnicodeWriter(SearxTestCase):
 
 class TestNewHmac(SearxTestCase):
     def test_bytes(self):
-        for secret_key in ['secret', b'secret', 1]:
-            if secret_key == 1:
-                with self.assertRaises(TypeError):
-                    webutils.new_hmac(secret_key, b'http://example.com')
-                continue
-            res = webutils.new_hmac(secret_key, b'http://example.com')
+        data = b'http://example.com'
+        with self.assertRaises(AttributeError):
+            webutils.new_hmac(b'secret', data)
+
+        with self.assertRaises(AttributeError):
+            webutils.new_hmac(1, data)
+
+        res = webutils.new_hmac('secret', data)
         self.assertEqual(res, '23e2baa2404012a5cc8e4a18b4aabf0dde4cb9b56f679ddc0fd6d7c24339d819')