tools: Fix detection of remote libvirt access in virt-qemu-sev-validate

The VM's firmware path is not extracted from the XML when invoking
virt-qemu-sev-validate in insecure mode and connecting to the local libvirt

virt-qemu-sev-validate --insecure --tk tek-tik.bin --domain test-sev-es
ERROR: Cannot access firmware path remotely

The test for remote access compares the return value from socket.gethostname()
to the return value from conn.getHostname(). The former doesn't always return
the fqdn, whereas the latter does. Use socket.getfqdn() instead.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

tools/virt-qemu-sev-validate

@@ -942,7 +942,7 @@ class LibvirtConfidentialVM(ConfidentialVM):
     def load_domain(self, uri, id_name_uuid, secure, ignore_config):
         self.conn = libvirt.open(uri)
 
-        remote = socket.gethostname() != self.conn.getHostname()
+        remote = socket.getfqdn() != self.conn.getHostname()
         if not remote and secure:
             raise InsecureUsageException(
                 "running locally on the hypervisor host is not secure")