Added check for proxycommand none and associated test as per Paramiko…

… Issue 415

Conflicts:
	tests/test_util.py

paramiko/config.py

@@ -73,6 +73,9 @@ def parse(self, file_obj):
                     'host': self._get_hosts(value),
                     'config': {}
                 }
+            elif key == 'proxycommand' and value.lower() == 'none':
+                # Proxycommands of none should not be added as an actual value. (Issue #415)
+                continue
             else:
                 if value.startswith('"') and value.endswith('"'):
                     value = value[1:-1]

tests/test_util.py

@@ -464,3 +464,23 @@ def test_safe_string(self):
         assert safe_vanilla == vanilla, err.format(safe_vanilla, vanilla)
         assert safe_has_bytes == expected_bytes, \
             err.format(safe_has_bytes, expected_bytes)
+
+    def test_proxycommand_none_issue_418(self):
+        test_config_file = """
+Host proxycommand-standard-none
+    ProxyCommand None
+
+Host proxycommand-with-equals-none
+    ProxyCommand=None
+    """
+        for host, values in {
+            'proxycommand-standard-none':    {'hostname': 'proxycommand-standard-none'},
+            'proxycommand-with-equals-none': {'hostname': 'proxycommand-with-equals-none'}
+        }.items():
+
+            f = StringIO(test_config_file)
+            config = paramiko.util.parse_ssh_config(f)
+            self.assertEqual(
+                paramiko.util.lookup_ssh_host_config(host, config),
+                values
+            )