Fixed flaky unit test.

[k82cn]

What this PR does / why we need it:
Fixed the following flaky unit test:

--- FAIL: TestGetEnvAsIntOrFallback (0.00s)
   Error Trace:    env_test.go:58
	Error:		Not equal: "strconv.ParseInt: parsing \"not-an-int\": invalid syntax" (expected)
			        != "strconv.Atoi: parsing \"not-an-int\": invalid syntax" (actual)
	Messages:	An error with value "strconv.ParseInt: parsing "not-an-int": invalid syntax" is expected but got "strconv.Atoi: parsing "not-an-int": invalid syntax".

FAIL
FAIL	k8s.io/kubernetes/pkg/util/env	0.005s

Release Note

[k8s-reviewable]

This change is 

[k8s-github-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: k82cn
We suggest the following additional approver: @brendandburns

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• pkg/OWNERS

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[k82cn]

Seems go 1.8 report different error message.

[root@ib15b13 kubernetes]# go version
go version go1.8 linux/amd64

[k8s-ci-robot]

@k82cn: The following test(s) failed:

Test name	Commit	Details	Rerun command
Jenkins Bazel Build	401a06d	link	@k8s-bot bazel test this
Jenkins unit/integration	401a06d	link	@k8s-bot unit test this

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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[k82cn]

go version issue, close it firstly.

[ixdy]

This was fixed in #44583.

[k82cn]

@ixdy , got that; thanks :).