Use va_list in openat_detour #800

Job	Run time
changed_files	43s
check_if_release_branch	1s
towncrier_check	44s
build mirrord CLI	0s
test_agent	3m 18s
test_agent_image	6m 29s
integration_tests	4m 58s
check-rust-docs	47s
lint	1m 41s
macos_tests	2m 33s
test_cli_image	3m 58s
lint_markdown	0s
e2e (docker)	6m 50s
e2e (containerd)	6m 59s
intellij_e2e_on_release_branch	0s
vscode_e2e_on_release_branch	0s
ci	1s
	39m 2s

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