libxl: fix qemu-dm path

qemu-dm is installed under libxl_libexec_path (not under
libxl_private_bindir_path).

Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
committer: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

tools/libxl/libxl.c

@@ -1733,7 +1733,7 @@ retry_transaction:
         goto out_close;
     if (!rc) { /* inner child */
         libxl__exec(null, logfile_w, logfile_w,
-                   libxl__abs_path(&gc, info->device_model, libxl_private_bindir_path()),
+                   libxl__abs_path(&gc, info->device_model, libxl_libexec_path()),
                    args);
     }