Fix AcidUtils.parseBaseOrDeltaBucketFilename handling of data loaded by LOAD DATA

Currently the AcidUtils.parseBaseOrDeltaBucketFilename considers files loaded to the table as original base files. We should fix that.
Also by checking the code for AcidUtils.parseBaseOrDeltaBucketFilename, I have found 2 things:

• The attribute copyNumber is not used anymore, so we should remove it
• The version of the parsedDelta we use here tries to check if the files are in raw format, or not. We do not need this information here, so we can use a different implementation of parseDelta, and avoid a remote call and file read.