Files: File transfers that succeed can still be marked failed if we experience a failure after transfer, but before chmod for exe's

[dvernon-tacc]

Joshua U was seeing an issue where file transfers were marked failed, but they really succeeded. The issue was that the transfer succeeded, but when we went back to look and see if the source was executable, we had a problem connecting. That check is there to decide if we should chmod the destination file. This can fail regardless of if the file is actually an executable or not. Here are a couple ideas:

1. Remember if it's executable from the check before we copy the file
2. Perhaps we could have created the file as executable instead of chmod-ing it.