PYTHON-1714 Add c extension use to client metadata

Fix tests
	- has_c is a func!

Author: aclark4life

test/asynchronous/test_client.py

@@ -343,7 +343,7 @@ async def test_read_preference(self):
 
     async def test_metadata(self):
         metadata = copy.deepcopy(_METADATA)
-        if has_c:
+        if has_c():
             metadata["driver"]["name"] = "PyMongo|c|async"
         else:
             metadata["driver"]["name"] = "PyMongo|async"
@@ -369,7 +369,7 @@ async def test_metadata(self):
         with self.assertRaises(TypeError):
             self.simple_client(driver=("Foo", "1", "a"))
         # Test appending to driver info.
-        if has_c:
+        if has_c():
             metadata["driver"]["name"] = "PyMongo|c|async|FooDriver"
         else:
             metadata["driver"]["name"] = "PyMongo|async|FooDriver"
@@ -1933,7 +1933,7 @@ def test_sigstop_sigcont(self):
     async def _test_handshake(self, env_vars, expected_env):
         with patch.dict("os.environ", env_vars):
             metadata = copy.deepcopy(_METADATA)
-            if has_c:
+            if has_c():
                 metadata["driver"]["name"] = "PyMongo|c|async"
             else:
                 metadata["driver"]["name"] = "PyMongo|async"

test/test_client.py

@@ -335,7 +335,7 @@ def test_read_preference(self):
 
     def test_metadata(self):
         metadata = copy.deepcopy(_METADATA)
-        if has_c:
+        if has_c():
             metadata["driver"]["name"] = "PyMongo|c"
         else:
             metadata["driver"]["name"] = "PyMongo"
@@ -361,7 +361,7 @@ def test_metadata(self):
         with self.assertRaises(TypeError):
             self.simple_client(driver=("Foo", "1", "a"))
         # Test appending to driver info.
-        if has_c:
+        if has_c():
             metadata["driver"]["name"] = "PyMongo|c|FooDriver"
         else:
             metadata["driver"]["name"] = "PyMongo|FooDriver"
@@ -1891,7 +1891,7 @@ def test_sigstop_sigcont(self):
     def _test_handshake(self, env_vars, expected_env):
         with patch.dict("os.environ", env_vars):
             metadata = copy.deepcopy(_METADATA)
-            if has_c:
+            if has_c():
                 metadata["driver"]["name"] = "PyMongo|c"
             else:
                 metadata["driver"]["name"] = "PyMongo"