file-posix: Fix aio=threads performance regression after enabling FUA

Kevin Wolfrequested to merge
kmwolf/centos-qemu-kvm:rhel-96854 into c10s

Merge Request Required Information

Summary of Changes

This fixes a performance regression introduced by the fix for https://issues.redhat.com/browse/RHEL-66064 with aio=threads.

Approved Development Ticket(s)

Jira: https://issues.redhat.com/browse/RHEL-96854

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