Before this change smb drives sometimes showed a fraction of the
correct size using `rclone about`.
This fixes the problem by switching the upstream library from
github.com/hirochachacha/go-smb2 to github.com/cloudsoda/go-smb2 which
has a fix for the problem.
The new library passes the integration tests.
Fixes#6733
Before this change we were putting connections into the connection
pool which had a local context in.
This meant that when the operation had finished the context was
cancelled and the connection became unusable.
See: https://forum.rclone.org/t/failed-to-sync-context-canceled/34017/
