qemu_process: Don't require a hugetlbfs mount for memfd

qemu_process: Don't require a hugetlbfs mount for memfd

The aim of qemuProcessNeedHugepagesPath() is to determine whether
a hugetlbfs mount point is required for given domain (as in
whether qemuBuildMemoryBackendProps() picks up
memory-backend-file pointing to a hugetlbfs mount point). Well,
when domain is configured to use memfd backend then that
condition can never be true. Therefore, skip creating domain's
private path under hugetlbfs mount points.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>