pickle CMSSW spec with protocolo=0 (and encode ?)

[belforte]

see

• Force pickle protocol=0 for the spec creation to be compatible with Py2/Py3 (Alan Malta Rodrigues) #10628
• Encode CMSSW picklearguments to bytes before loading it (Alan Malta Rodrigues) #10648

from
https://github.com/dmwm/WMCore/releases/tag/1.5.0

I do not know if we need for crab to make PSet.pkl in py3 and read in py2... but this is something to keep in mind as soon as we get over dmwm/CRABServer#6653 and start to actually run py3 payloads.

[belforte]

refs:
dmwm/WMCore#10628
dmwm/WMCore#10648

[belforte]

see also https://github.com/cms-sw/cmssw-wm-tools/blob/30b626d030b7b11f83fe4e0385ce303e83d3fcdf/bin/edm_pset_tweak.py#L142
and
https://github.com/cms-sw/cmssw-wm-tools/blob/30b626d030b7b11f83fe4e0385ce303e83d3fcdf/bin/edm_pset_tweak.py#L48-L50

[belforte]

We really should do it.

[belforte]

as @khurtado suggested, it would be better to use the ad-hoc common method
https://github.com/cms-sw/cmssw-wm-tools/blob/master/bin/edm_pset_pickler.py

[belforte]

better to make a different issue about replacing "my code" with "common code" and keep this closed, since it works.