erp5_web: fix a typo in WebSite_viewSiteMapAsXML.

8 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

01:19:50

passed ERP5.PerformanceTest-Master

00:26:56

failed ERP5.UnitTest-Master

02:34:11

failed ERP5.UnitTest-Master.Medusa

02:13:43

passed SlapOS.Eggs.UnitTest-Master.Python2

00:13:55

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:32

passed SlapOS.Eggs.UnitTest-Master.Python2

00:20:52

passed SlapOS.Eggs.UnitTest-Master.Python3

00:27:04