auto-t: add shell test

This is merely an empty test that can act as a sandbox for the new
--shell command. It was not named with 'test' so that autotesting
will skip it.

This test is not very useful for virtual hardware testing
(mac80211_hwsim), but very useful for USB/PCI passthrough. When
setup correctly, you can now pass through a single device and test
against real networks with a minimal kernel.

autotests/shell/hw.conf

@@ -0,0 +1,2 @@
+[SETUP]
+num_radios=1

autotests/shell/shell_test.py

@@ -0,0 +1,20 @@
+import unittest
+import sys
+
+sys.path.append('../util')
+
+class Test(unittest.TestCase):
+
+    def test_connection_success(self):
+        pass
+
+    @classmethod
+    def setUpClass(cls):
+        pass
+
+    @classmethod
+    def tearDownClass(cls):
+        pass
+
+if __name__ == '__main__':
+    unittest.main(exit=True)