PFN checking should accept mixed protocols

[bari12]

Motivation

For the add_files_to_datasets() call a list of attachments with pfns can be given to Rucio. In the case that these PFNs have different protocols, the PFN check fails, since the protocol is only initialised once (with the last protocol of the list) and assumes all PFNs have the same protocol.

E.g.:

[{'scope': 'panda', 'name': 'panda.0908235529.354928.lib._19050738', 'dids': [{'adler32': '7dd69a5f', 'name': 'panda.0908235529.354928.lib._19050738.18598150846.lib.tgz', 'bytes': 72565480L, 'pfn': 'srm://f-dpm001.grid.sinica.edu.tw:8446/srm/managerv2?SFN=/dpm/grid.sinica.edu.tw/home/atlas/atlasscratchdisk/rucio/panda/23/40/panda.0908235529.354928.lib._19050738.18598150846.lib.tgz', 'meta': {'panda_id': 4478387679, 'guid': '81789F3E-572E-4DFA-BE8B-04667522031E'}, 'scope': 'panda'}, {'adler32': '048f10bf', 'name': 'panda.0908235529.354928.lib._19050738.18598150847.log.tgz', 'bytes': 72614448L, 'pfn': 'davs://f-dpm000.grid.sinica.edu.tw:443/dpm/grid.sinica.edu.tw/home/atlas/atlasscratchdisk/rucio/panda/80/c7/panda.0908235529.354928.lib._19050738.18598150847.log.tgz', 'meta': {'panda_id': 4478387679, 'guid': 'c71d6bf8-d372-437a-b0a8-efeb3dacbfa3'}, 'scope': 'panda'}], 'rse': 'TAIWAN-LCG2_SCRATCHDISK'}]

ATLAS JIRA Link: https://its.cern.ch/jira/browse/RUCIO-2890

Modification

PFN check needs to initialise a protocol for each protocol-group of PFNs.