only using getfixturevalue for test

Author: burnout87

astroquery/desi/tests/test_desi.py

@@ -53,10 +53,7 @@ def get_readable_fileobj_mockreturn(filename, **kwargs):
             if f is not None:
                 f.close()
 
-    try:
-        mp = request.getfixturevalue("monkeypatch")
-    except AttributeError:  # pytest < 3
-        mp = request.getfuncargvalue("monkeypatch")
+    mp = request.getfixturevalue("monkeypatch")
 
     mp.setattr(commons, 'get_readable_fileobj',
                get_readable_fileobj_mockreturn)