Generate polycubectl config directory with traverse permission (#248)

* Generate polycubectl config directory with traverse permission

Author: FedeParola

src/polycubectl/config/config.go

@@ -85,7 +85,10 @@ func saveConfig(config Config) error {
 		return fmt.Errorf("error during json Marshal: %s", err.Error())
 	}
 
-	os.MkdirAll(home+PathToConfigFile, 0600)
+	// Create a directory for the config file with read, write and execute
+	// permission for the current user (700)
+	// (both w and x are needed to edit the content of the dir)
+	os.MkdirAll(home+PathToConfigFile, 0700)
 
 	f, err := os.Create(home + PathToConfigFile + ConfigFile)
 	defer f.Close()