fixed error detection for tsig key

init.py

     out = container.exec_run(['pdnsutil', 'set-meta', zone, 'TSIG-ALLOW-DNSUPDATE', key_name])
     if out is not None:
         out = out.decode('UTF-8')
-        return out == 'Enabled TSIG key %s for %s\n' % (key_name, zone) # might to strict, but as we can not get return code
+        return out == 'Set \'%s\' meta TSIG-ALLOW-DNSUPDATE = %s\n' % (zone, key_name) # might to strict, but as we can not get return code
     return False
 
 def main():
             print('Adding TSIG %s to zone %s...' % (args.tsig_key_name, zone))
             if not add_tsig_key_to_zone(container, zone, args.tsig_key_name):
                 print('Failed to add TSIG key to zone: Unknown error')
+                return 8
 
     print('DHCP_TSIG_KEY_NAME=%s' % (args.tsig_key_name))
     print('DHCP_TSIG_KEY_ALGO=%s' % (args.tsig_key_algo))