config.BooleanOption: fix handling argparse options

The argparse option now reverse the default value set in configuration 
file instead of only the default value set on adding the configuration 
option.

mylib/config.py

@@ -78,6 +78,14 @@ class BaseOption:  # pylint: disable=too-many-instance-attributes
         """ Get option value from ConfigParser """
         return self.config.config_parser.get(self.section.name, self.name)
 
+    @property
+    def _default_in_config(self):
+        """ Get option default value considering current value from configuration """
+        return (
+            self._from_config if self._isset_in_config_file
+            else self.default
+        )
+
     def isset(self):
         """ Check if option is defined in the loaded configuration file """
         return self._isset_in_config_file or self._isset_in_options
@@ -243,9 +251,26 @@ class BooleanOption(BaseOption):
         """ Format value as stored in configuration file """
         return super().to_config(value).lower()
 
+    @property
+    def _isset_in_options(self):
+        """ Check if option is defined in registered arguments parser options """
+        return (
+            self.config.options
+            and not self.no_arg
+            and getattr(self.config.options, self.parser_dest)
+        )
+
+    @property
+    def _from_options(self):
+        """ Get option from arguments parser options """
+        return (
+            not self._default_in_config if self._isset_in_options
+            else self._default_in_config
+        )
+
     @property
     def parser_action(self):
-        return "store_" + str(bool(not self.default)).lower()
+        return "store_true"
 
     @property
     def parser_type(self):
@@ -258,7 +283,7 @@ class BooleanOption(BaseOption):
             self.arg if self.arg else
             '--{0}-{1}-{2}'.format(
                 self.section.name,
-                'enable' if not self.default else 'disable',
+                'enable' if not self._default_in_config else 'disable',
                 self.name
             ).lower().replace('_', '-')
         )