stack/erp5: patch RestrictedPython to compile with print_function

Every restricted python code on python2 will be compiled as if it had
`from __future__ import print_function`, to ease transition away from
python2.

To update project code, 2to3 from python2.7 seems to do a good job.
Invoking like from the root of a repository rewrite all scripts:

    2to3  --write --nobackups --no-diffs --fix=print .
Status Job ID Name Coverage
  External
passed Cloudooo.UnitTest-Master

00:09:01

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

00:27:24

failed ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:01:41

passed SlapOS.Eggs.UnitTest-Master.Python2

00:13:09

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:28

passed SlapOS.Eggs.UnitTest-Master.Python3Next

00:14:14

failed SlapOS.SoftwareReleases.IntegrationTest-Master

06:14:36

failed SlapOS.Theia.ResilienceTest-Master-ERP5

04:39:51

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:27:38

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

07:43:58

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

00:33:37

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

00:27:36

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

00:27:05

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

00:27:50

passed SlapOS.Eggs.UnitTest-Master.Python2

00:15:44

passed SlapOS.Eggs.UnitTest-Master.Python2

00:13:22

passed SlapOS.Eggs.UnitTest-Master.Python2

00:15:30

passed SlapOS.Eggs.UnitTest-Master.Python2

00:14:06

passed SlapOS.Eggs.UnitTest-Master.Python2

00:14:29

passed SlapOS.Eggs.UnitTest-Master.Python2

00:17:40

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:14

passed SlapOS.Eggs.UnitTest-Master.Python3

00:17:13

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:32

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:13

passed SlapOS.Eggs.UnitTest-Master.Python3

00:16:01

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:13

passed SlapOS.Eggs.UnitTest-Master.Python3Next

00:14:50

passed SlapOS.Eggs.UnitTest-Master.Python3Next

00:15:43

passed SlapOS.Eggs.UnitTest-Master.Python3Next

00:14:24

passed SlapOS.Eggs.UnitTest-Master.Python3Next

00:14:57

passed SlapOS.Eggs.UnitTest-Master.Python3Next

00:14:26

passed SlapOS.Eggs.UnitTest-Master.Python3Next

00:15:38

failed SlapOS.SoftwareReleases.IntegrationTest-Master

07:04:48

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:27:34

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:28:05

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:41:39

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:31:27

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:01:39

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:01:42

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:01:46

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:01:43