scsi: prefer UUID to VM name for the initiator name

The UUID is unique even across multiple hosts, thus it is
better than a VM name even if it is less user-friendly.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

stubs/uuid.c

@@ -0,0 +1,12 @@
+#include "qemu-common.h"
+#include "sysemu/sysemu.h"
+#include "qmp-commands.h"
+
+UuidInfo *qmp_query_uuid(Error **errp)
+{
+    UuidInfo *info = g_malloc0(sizeof(*info));
+
+    info->UUID = g_strdup(UUID_NONE);
+    return info;
+}
+