fix(module/shell): expand user directory in command spec

Make sure that ~/ is expanded to the user's home directory in the
command specified for the shell module.

fixes #1002

bumblebee_status/modules/contrib/shell.py

@@ -41,6 +41,7 @@ def __init__(self, config, theme):
         super().__init__(config, theme, core.widget.Widget(self.get_output))
 
         self.__command = self.parameter("command", 'echo "no command configured"')
+        self.__command = os.path.expanduser(self.__command)
         self.__async = util.format.asbool(self.parameter("async"))
 
         if self.__async: