Promote 'model' from state to dimension for Macs.

appengine/swarming/swarming_bot/api/os_utilities_test.py

Index: appengine/swarming/swarming_bot/api/os_utilities_test.py
diff --git a/appengine/swarming/swarming_bot/api/os_utilities_test.py b/appengine/swarming/swarming_bot/api/os_utilities_test.py
index a997cc6f76a0c6a06c4b9f11821ab5989faf0676..96a8675820b63856e632c37c072d27ec79b31145 100755
--- a/appengine/swarming/swarming_bot/api/os_utilities_test.py
+++ b/appengine/swarming/swarming_bot/api/os_utilities_test.py
@@ -98,6 +98,7 @@ class TestOsUtilities(auto_stub.TestCase):
     actual.discard(u'hidpi')
     expected = {u'cores', u'cpu', u'gpu', u'id', u'os', u'pool'}
     if sys.platform == 'darwin':
+      expected.add(u'mac_model')
       expected.add(u'xcode_version')
     self.assertEqual(expected, actual)
 
@@ -112,7 +113,6 @@ class TestOsUtilities(auto_stub.TestCase):
     if sys.platform in ('cygwin', 'win32'):
       expected.add(u'cygwin')
     if sys.platform == 'darwin':
-      expected.add(u'model')
       expected.add(u'xcode')
     if sys.platform == 'win32':
       expected.add(u'integrity')