vm_control: fix double-close on VmIrqRequest::AllocateOneMsi
vm_control: fix double-close on VmIrqRequest::AllocateOneMsi

The EventFd that wraps the MaybeOwnedFd will close the fd, but so will
MaybeOwnedFd, causing a double-close.

BUG=None
TEST=strace crosvm run

Change-Id: I277386cd20eaa1a8187274cc16084b1936355012
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2034026
Commit-Queue: Zach Reizner <3374927928a53d04457674c546bd4de57c2044ec@chromium.org>
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Reviewed-by: Xiong  Zhang <887154684953c1d7bc9f653d05b20c8de98c15bc@intel.corp-partner.google.com>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

google/crosvm,google/crosvm,google/crosvm,google/crosvm