[Libguestfs] (no subject)

Hi, we needed these changes when we had to build a guest image compatible with a starting guest image but not backed by it in any way• We needed some tool to check our progress, comparing original and• rebuilt (from scratch) images, and virt-diff seemed the best option, but• we had to soften the comparison to reduce the noise in the output. I added some options to ignore certain informations when comparing. I built and tested it, and now for example, one can ignore file permission with --no-compare-perms, and still see permissions shown when files differ by other criterias.