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While trying to set up autoxflate I ran into a bug where autoxflate doesn't seem to work with copy jobs (in Bareos 21 - and still an issue currently).

This test does the following:

1. Create a full backup with LZ4 compression (as per SelfTest fileset config)
2. Copy full backup to other pool and decompress (as per FileStorage2 device config)
3. Restore copied job

Once the copy is restored I'd expect the files to be the same as the original files. While the restore job does end in success ("Restore OK"), it doesn't actually seem to restore anything, just a couple of empty files.

So, after some investigation it turns out to be a problem caused by several things:

1. bSdEventSetupRecordTranslation is not called for migrate/copy jobs, causing autoxflate to not be able to set up inflate/deflate buffers
2. autoxflate would in certain cases not set up inflate/deflate buffers anyways when it should depending on the configuration
3. when LZ4 fails to decompress it seems to do so silently and just returns 0 bytes instead of logging an error, i.e., corrupted data is written to disk. This is not the case when e.g. GZIP is used, in which case an error is logged and it falls back to writing the compressed stream to disk, so data is not corrupted.

This PR fixes 1 and 2 and also adds a check to ensure the inflate buffer is set up. Autoxflate should now also work with migrate/copy jobs and the test passes.
I've also fixed a small memory leak which would occur when autoxflate detects that the deflate buffer is not set up.

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