Add leading zeros to adler32 checksum to ensure 8 chars length - wma branch

[amaltaro]

wmagent branch version of #9809

Plus, a second fix to the RucioInjector, for cases where the file information has already been persisted in the database with an adler32 value that does not match this Rucio server regex:
'^[a-fA-F\\d]{8}$'

I tested some print-statement only in one of the production agents, and it seems to do the trick:

2020-07-08 17:59:12,790:140568300840704:INFO:RucioInjectorPoller:AMR current adler32 37cc05 and new adler32 0037cc05
2020-07-08 17:59:12,790:140568300840704:INFO:RucioInjectorPoller:AMR current adler32 499110dc and new adler32 499110dc
...
2020-07-08 17:59:12,805:140568300840704:INFO:RucioInjectorPoller:AMR current adler32 995c1a90 and new adler32 995c1a90
2020-07-08 17:59:12,805:140568300840704:INFO:RucioInjectorPoller:AMR current adler32 5e3a80 and new adler32 005e3a80
2020-07-08 17:59:12,805:140568300840704:INFO:RucioInjectorPoller:AMR current adler32 61cdb8e1 and new adler32 61cdb8e1
2020-07-08 17:59:12,805:140568300840704:INFO:RucioInjectorPoller:AMR current adler32 655dc518 and new adler32 655dc518

[amaltaro]

@todor-ivanov @nsmith- this is the patch I'm planning to push to the production agents. Please let me know if you see anything wrong with this, otherwise I will patch all of them tonight (CERN time).

[amaltaro]

All the agents have been patched.

[amaltaro]

Fix #9810 - Add leading zeros to adler32 checksum to ensure 8 chars length

[nsmith-]

Thanks for the quick patch!

[todor-ivanov]

Hi @amaltaro I also tested this manually last night and the length of the result was exactly 8 chars. So I think it is good.