[py2py3] Remove strings-related temporary workarounds, those needed only for py2py3 dual stack

[mapellidario]

Impact of the new feature WMCore in general

Is your feature request related to a problem? Please describe.

When we switch to python 3, we can remove some of the compatibility code that is in place to make sure that dmwm/WMCore works in py2/py3 dual stack. We focus this issue on deprecating management of strings.

Describe the solution you'd like

• [ ] In #10299 we used _unicode() as a temporary workaround. We should remove it when we finish the migration and we drop py2 support. We can just use str and remove that _unicode() method completely from: WMQuality/Emulators/DBSClient/MockDbsApi.py and WMQuality/Emulators/RucioClient/MockRucioApi.py
• [ ] #10342: also uses the same _unicode() logic to lookup keys in the python dictionary (json file).
• [ ] #10319: src/python/WMCore/MicroService/TaskManager.py: remove keyhash.update(query.encode('ascii'))

Describe alternatives you've considered We can leave it as it is, but we should really consider removing temporary workarounds :)

[amaltaro]

@mapellidario just to make sure I understood what is expected from this issue. Is it supposed to happen only when WMCore is no longer supporting python2?

[mapellidario]

Well, eventually we changed the code in all of those places:

• TaskManager: we are using encodeUnicodeToBytesConditional(query, condition=PY3) instead of query.encode('ascii')
• we made some changes recently in MockDbsApi and MockRucioApi that supersede what i was describing in this issue.

Maybe we can change this issue in: "Change encodeUnicodeToBytesConditional(query, condition=PY3) to encodeUnicodeToBytes(query) after dropping support to py2", or something like that.

In any case you are correct, this issue was about cleaning up a bit our code after we drop support to py2