libvfio-user: move submodule pointer to e817d2e.

This pulls in fix "test: don't leave global pointing to
stack memory".

Fixes SPDK issue #3027.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: I321b5161b208437d67eb33028dbe1aa8a90f576a
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/18301


Reviewed-by: Kamil Godzwon <kamilx.godzwon@intel.com>
Reviewed-by: Michal Berger <michal.berger@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>