[Libguestfs] [PATCH v2v 0/7] Mostly fix "make check-slow"

$ make && make check-slow I hadn't run this set of tests in a while and they were all failing. Luckily that was easy to fix (see patches 1 and 2). However we need to change the mix of guests being tested, dropping some old ones which are no longer testable, and adding some newer ones. There is one slow test which still fails (test-v2v-trim.sh) which I'm still looking at. Rich.