Description: Don't pytest.mark fixtures

The tests using it already have the same mark

Author: Rebecca N. Palmer <rebecca_palmer@zoho.com>
Bug-Debian: https://bugs.debian.org/1123337
Forwarded: no

--- a/rpy2-robjects/src/rpy2/ipython/tests/test_rmagic.py
+++ b/rpy2-robjects/src/rpy2/ipython/tests/test_rmagic.py
@@ -67,8 +67,6 @@ def test_get_valid_device_invalid(name,
         rmagic.get_valid_device(name, devices_dict=devices_dict)
 
 
-@pytest.mark.skipif(IPython is None,
-                    reason='The optional package IPython cannot be imported.')
 @pytest.fixture(scope='module')
 def clean_globalenv():
     yield