[Libguestfs] [PATCH 0/2] libguestfs: Rust binding build error and warning fixes

There is actually a build error on master right now, probably came with the new cargo version. The first patch will fix that error (just a one liner). The second patch will implement the necessary traits for the internal Error type to be a proper Rust error. This caused issues with manual error handling and with error handling crates like anyhow.