test_pyecdsa: remove unused variable

Author: tomato42

src/ecdsa/test_pyecdsa.py

@@ -1378,8 +1378,6 @@ def do_test_to_openssl(self, curve, hash_name="SHA1"):
         pass
 
     def do_eddsa_test_to_openssl(self, curve):
-        curvename = curve.name.upper()
-
         if os.path.isdir("t"):
             shutil.rmtree("t")
         os.mkdir("t")