Only define cookiedomain if defined

Change-Id: I26210c966720d74ba35dfadda288f4bef4b2030f
diff --git a/gerrit/etc/gerrit.config.template b/gerrit/etc/gerrit.config.template
index dc11036..bc9fdcc 100644
--- a/gerrit/etc/gerrit.config.template
+++ b/gerrit/etc/gerrit.config.template
@@ -10,7 +10,10 @@
 [auth]
   type = ldap
   gitBasicAuth = true
-  cookiedomain = .{{ COOKIE_DOMAIN }}
+  {% if COOKIE_DOMAIN is defined %}
+    cookiedomain = .{{ COOKIE_DOMAIN }}
+  {% endif %}
+
 [ldap]
   server = {{ LDAP_SERVER }}
   username = {{ LDAP_USERNAME }}
diff --git a/gerrit/setup_gerrit.py b/gerrit/setup_gerrit.py
index d1b10b9..2e1abc3 100755
--- a/gerrit/setup_gerrit.py
+++ b/gerrit/setup_gerrit.py
@@ -136,6 +136,8 @@
     else:
         raise e
 
+if 'HOSTED_ZONE_NAME' in os.environ:
+    config_for_template['COOKIE_DOMAIN'] = os.getenv('HOSTED_ZONE_NAME')
 with open(GERRIT_CONFIG_DIRECTORY + "gerrit.config", 'w',
           encoding='utf-8') as f:
     config_for_template.update({
@@ -145,8 +147,7 @@
         'LDAP_GROUP_BASE': config['ldap']['groupBase'],
         'SMTP_SERVER': config['smtp']["server"],
         'SMTP_USER': config['smtp']["user"],
-        'SMTP_DOMAIN': config['smtp']["domain"],
-        'COOKIE_DOMAIN': os.getenv('HOSTED_ZONE_NAME'),
+        'SMTP_DOMAIN': config['smtp']["domain"]
     })
     f.write(template.render(config_for_template))