Fix for python3 in test_update_user1 and test_update_hook1

Author: Costin Bleotu

tests/interface_test.py

@@ -202,7 +202,7 @@ def test_update_user1(self):
             .build()
 
         def callback(request):
-            data = json.loads(request.body)
+            data = json.loads(request.body.decode('utf8'))
             self.assertEqual(data["login_name"], "loginname")
             self.assertEqual(data["full_name"], "Example User")
             self.assertEqual(data["email"], "user@example.com")
@@ -313,7 +313,7 @@ def test_update_hook1(self):
             .build()
 
         def callback(request):
-            data = json.loads(request.body)
+            data = json.loads(request.body.decode('utf8'))
             self.assertEqual(data["config"]["url"], "http://newurl.com/hook")
             self.assertEqual(data["events"], ['issues_comments'])
             self.assertEqual(data["active"], True)