slapos_web_deploy: install python2 even on newest OS

actually ansible uses /usr/bin/python as defaut interpreter. Use this
temporary workaround until we can set properly the ansible python
interpreter. See https://docs.ansible.com/ansible/latest/reference_appendices/python_3_support.html
30 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed SlapOS.Eggs.UnitTest-Master.Python2

00:35:02

passed SlapOS.Eggs.UnitTest-Master.Python3

00:23:47

passed SlapOS.Eggs.UnitTest-Master.Python2

00:33:15

passed SlapOS.Eggs.UnitTest-Master.Python2

00:34:21

failed SlapOS.Eggs.UnitTest-Master.Python2

00:38:15

passed SlapOS.Eggs.UnitTest-Master.Python2

00:32:39

passed SlapOS.Eggs.UnitTest-Master.Python2

00:43:08

passed SlapOS.Eggs.UnitTest-Master.Python2

00:40:05

passed SlapOS.Eggs.UnitTest-Master.Python2

00:38:52

passed SlapOS.Eggs.UnitTest-Master.Python2

00:41:55

passed SlapOS.Eggs.UnitTest-Master.Python2

00:32:42

passed SlapOS.Eggs.UnitTest-Master.Python2

00:35:27

passed SlapOS.Eggs.UnitTest-Master.Python2

00:42:20

failed SlapOS.Eggs.UnitTest-Master.Python2

00:35:45

passed SlapOS.Eggs.UnitTest-Master.Python2

00:34:21

passed SlapOS.Eggs.UnitTest-Master.Python3

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:28

passed SlapOS.Eggs.UnitTest-Master.Python3

00:59:56

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:40

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:13

failed SlapOS.Eggs.UnitTest-Master.Python3

00:13:56

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:52

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:01

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:08

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:01

passed SlapOS.Eggs.UnitTest-Master.Python3

00:16:28

passed SlapOS.Eggs.UnitTest-Master.Python3

00:16:34

passed SlapOS.Eggs.UnitTest-Master.Python3

04:13:46

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:54

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:14