[libvirt] [PATCH 0/3] Fix domain restore problems when selinux is enforcing

Prior to this patch series, restoring a domain with selinux set to enforcing would fail, because the function that sets the label on the file to allow qemu to read it did not have the name of the file (see the comments in the individual patches). A patch from Jamie Stranboge (2b57478ef0a0a983cc6a47b98300c8359f9708d0) added the filename to the args passed down into the security driver; the first patch of this series takes advantage of that to properly set the label. Patches 2 and 3 solve a problem with restoring a domain from an NFS share - in this case the selinux functions will fail (as will functions trying to set the uid of the file, if it is a root-squashed share). The solution to this is just ignore the failure. qemudDomainSaveFlag previously had a bit of code that detected if a particular path was on an NFS share; this code was moved into a utility function so it could be re-used during domain restore - if the security driver fails to set the label, and the file is on an NFS share, we ignore the failure, otherwise we behave as before.