Core: raise an error if the configuration file does not exist (fix issue #1)

easycloud/core/metaconfmanager.py

@@ -24,7 +24,8 @@ class MetaConfManager(ABC):
         else:
             self._config_file = config_file
 
-        self.parser.read(open(self._config_file, "r"))
+        # NOTE: this will raise an error if the configuration file does not exist
+        self.parser.read_file(open(self._config_file, "r"))
 
         self.read_login_data()
         self.read_platform_options()