[1.2] dmz: overlay: minor fixups #7034

Job	Run time
cross-i386	1m 8s
test (ubuntu-20.04, 1.22.x, rootless, -race)	7m 24s
test (ubuntu-20.04, 1.22.x, rootless)	6m 58s
test (ubuntu-20.04, 1.22.x, -race)	7m 51s
test (ubuntu-20.04, 1.22.x)	7m 5s
test (ubuntu-20.04, 1.23.x, rootless, -race)	7m 50s
test (ubuntu-20.04, 1.23.x, rootless)	7m 14s
test (ubuntu-20.04, 1.23.x, -race)	7m 43s
test (ubuntu-20.04, 1.23.x)	7m 11s
test (ubuntu-20.04, 1.23.x, criu-dev)	7m 36s
test (ubuntu-24.04, 1.22.x, rootless, -race)	9m 57s
test (ubuntu-24.04, 1.22.x, rootless)	10m 56s
test (ubuntu-24.04, 1.22.x, -race)	8m 59s
test (ubuntu-24.04, 1.22.x)	7m 25s
test (ubuntu-24.04, 1.23.x, rootless, -race)	9m 53s
test (ubuntu-24.04, 1.23.x, rootless)	11m 13s
test (ubuntu-24.04, 1.23.x, -race)	8m 47s
test (ubuntu-24.04, 1.23.x)	6m 59s
test (ubuntu-24.04, 1.23.x, criu-dev)	7m 33s
test (actuated-arm64-6cpu-8gb, 1.23.x, rootless)	11m 26s
test (actuated-arm64-6cpu-8gb, 1.23.x)	7m 53s
all-done	1s
	2h 49m 2s

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