Do not update /etc/hosts file if target hostname is not set

helpers.py

@@ -105,6 +105,9 @@ def fab_add_to_hosts(ip, site_hostname):
     :param site_hostname:
     :return:
     """
+    if not site_hostname:
+        return
+
     if confirm(green('Do you want add to the /etc/hosts the line "{}    {}"? '
                      'If you say yes you will be able to visit the site using a more frienldy url '
                      '"http://{}".'.format(ip, site_hostname, site_hostname))):
@@ -123,6 +126,9 @@ def fab_remove_from_hosts(site_hostname):
     :param site_hostname:
     :return:
     """
+    if not site_hostname:
+        return
+
     print(green('Enter your password to remove the {} from your /etc/hosts file'.format(site_hostname)))
     local('sudo sed -i "/{}/d" /etc/hosts'.format(site_hostname))