Do not require space tokens for SRM

[bbockelm]

At many CMS sites, space tokens are not used even when SRM is utilized. However, it's not currently possible to skip this setting.

It may be as simple as setting the space token to the empty string (``), which could be done automatically if not specified.

However, there might be hidden dependencies that want a non-empty-string space token. Needs investigation.

[nataliaratnikova]

Currently Rucio unconditionally passes spacetoken json parameter to FTS job. No matter what value is passed, this causes fts error on CMS sites which do not support spacetokens.
The desired behavior is: if space_token is not in the 'extended_attributes' , do not add spacetoken to fts json.

[bbockelm]

Lines that need fixing:

• https://github.com/rucio/rucio/blob/master/lib/rucio/transfertool/fts3.py#L171
• https://github.com/rucio/rucio/blob/master/lib/rucio/daemons/conveyor/common.py#L165

[nataliaratnikova]

Hi @bbockelm , how do I now define an RSE so that it would not pass the spacetoken to FTS?
Adding 'srm' protocol still requires a non-empty spacetoken argument :
# rucio-admin rse add-protocol --hostname 'stormfe1.pi.infn.it' --scheme 'srm' --prefix '/cms/store/test/rucio' --web-service-path '/srm/managerv2?SFN=' --port '8444' --impl 'rucio.rse.protocols.gfalv2.Default' --domain-json '{"wan": {"read": 1, "write": 1, "delete": 1, "third_party_copy": 1}}' --space-token '' T2_IT_Pisa
Error: space-token and web-service-path must be provided for SRM endpoints.