Skip TestInferDevice if no GPU support

Summary:
Working towards https://github.com/caffe2/caffe2/pull/817.
```
E           AttributeError: Method CopyCPUToGPU is not a registered operator. Did you mean: []
```
https://travis-ci.org/caffe2/caffe2/jobs/243867951
Closes https://github.com/caffe2/caffe2/pull/818

Differential Revision: D5276735

Pulled By: akyrola

fbshipit-source-id: 35d9df19330ae522037e8a5d721d83dc2e5aa4dc
diff --git a/caffe2/python/core_test.py b/caffe2/python/core_test.py
index ca0ff03..44138e8 100644
--- a/caffe2/python/core_test.py
+++ b/caffe2/python/core_test.py
@@ -441,6 +441,7 @@
         self.assertEqual(net.Proto().op[0].name, '{}:{}'.format(filename, line))
 
 
+@unittest.skipIf(not workspace.has_gpu_support, 'No GPU support')
 class TestInferDevice(test_util.TestCase):
 
     def setUp(self):