Fixed premium address replacement.

tester.py

@@ -431,7 +431,7 @@ class Tester():
                 recipients = recipients.replace('sysadmin@ubicast.eu', '').replace(',,', ',')
             elif utils.get_conf('PREMIUM_SUPPORT') != '0':
                 system_domain = '[PREMIUM] %s' % system_domain
-                recipients.replace('sysadmin@ubicast.eu', 'sysadmin+premium@ubicast.eu')
+                recipients = recipients.replace('sysadmin@ubicast.eu', 'sysadmin+premium@ubicast.eu')
             recipients = recipients.strip(',')
             if not recipients:
                 log('No recipients defined for email sending. Set a value for EMAIL_ADMINS.')