web_deploy: use download_playbook function directly

See merge request !426
3 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed SlapOS-Master.UnitTest-Master

01:20:00

passed SlapOS.Eggs.UnitTest-Master.Python2

00:12:30

failed SlapOS.Eggs.UnitTest-Master.Python3

00:13:05