ingest/ledgerbackend: change captive-core unit tests to use storage path in /tmp

[sreuland]

What version are you using?

2.15.1

What did you do?

go test ./ingest/ledgerbackend/...

What did you expect to see?

no temporary test files generated during test execution in checked out repo paths

What did you see instead?

several ./ingest/ledgerbackend/captive-core-xyz/ sub-folders were created in current checked out working directory

[leighmcculloch]

change captive-core unit tests to cleanup storage path at finish

Is it possible to change the storage paths to a tmp directory, by using os.MkdirTemp? So that tests aren't writing new files to the repo during run.

[sreuland]

yes, changed desired output to that behavior, probably should remove files at end of tests in any case.

[2opremio]

Related: https://github.com/stellar/go/pull/3727/files (it contains how some tests were updated to write to /tmp for the same reason).