[Libguestfs] [PATCH 0/6] tests: Fix handling of device API parameters (RHBZ#1477623).

https://bugzilla.redhat.com/show_bug.cgi?id=1477623 The first two patches are cleanups. The third patch changes the way that we handle Device and Dev_or_Path parameters so that a parameter marked as such can really only contain a block device name (and not, for instance, a chardev). Using a chardev here caused hangs in the API. The next two patches fix API usage to conform to this new stricter checking. I removed the ability to use "/dev/urandom" (and similar) non-block devices in place of block devices in such APIs as guestfs_copy_device_to_device. Last patch adds a regression test. Rich.