Creating a checksum of a larger local file or network file will result in an empty sha256sum.txt because Kleopatra just uses "waitForFinished()" which defaults to a timeout of 30 seconds. We should trust our tools enough to use an infinite timeout. But we better replace the shasum command from gpg4win, so they might also do proper progress and use libgcrypt. I open another task for this.

So this will be just a quick fix for the timeout.