Replace setting_type.new() with setting_type()

When `setting_type` is `NM.SettingMatch`, `setting_type.new()` will not
work because `nm_setting_match_new()` symbol is only exposed and usable
since libnm version 1.32 (using `setting_type.new()` is equivalent to
call libnm function `nm_setting_*_new()`).

Function `setting_type()` will always construct an instance of that
`setting_type` and will not need a workaround when `setting_type` is
`NM.SettingMatch`. So drop `setting_type.new()` in favor of
`setting_type()`.

Signed-off-by: Wen Liang <liangwen12year@gmail.com>

library/network_connections.py

@@ -705,7 +705,7 @@ class NMUtil:
     def connection_ensure_setting(self, connection, setting_type):
         setting = connection.get_setting(setting_type)
         if not setting:
-            setting = setting_type.new()
+            setting = setting_type()
             connection.add_setting(setting)
         return setting