Rework how we use stevedore in BAT transport

Registered by Jedrzej Nowak

We should raise an error on transport use, not when file is loaded.

https://review.openstack.org/#/c/281163/ + https://bugs.launchpad.net/solar/+bug/1546436

Blueprint information

Status:
Not started
Approver:
None
Priority:
Undefined
Drafter:
Jedrzej Nowak
Direction:
Approved
Assignee:
Maciej Kwiek
Definition:
New
Series goal:
None
Implementation:
Unknown
Milestone target:
milestone icon 0.3.0

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Gerrit topic: https://review.openstack.org/#q,topic:bp/rework-bat-transport-stevedore,n,z

Addressed by: https://review.openstack.org/289888
    Load solar.transports.{mode} in BatTransport

(?)

Work Items

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