Avoid warnings about POD_NAMESPACE not set when they are irrelevant

[antoninbas]

Fixes #924

[antrea-bot]

Thanks for your PR.
Unit tests and code linters are run automatically every time the PR is updated.
E2e, conformance and network policy tests can only be triggered by a member of the vmware-tanzu organization. Regular contributors to the project should join the org.

The following commands are available:

• /test-e2e: to trigger e2e tests.
• /skip-e2e: to skip e2e tests.
• /test-conformance: to trigger conformance tests.
• /skip-conformance: to skip conformance tests.
• /test-whole-conformance: to trigger all conformance tests on linux.
• /skip-whole-conformance: to skip all conformance tests on linux.
• /test-networkpolicy: to trigger networkpolicy tests.
• /skip-networkpolicy: to skip networkpolicy tests.
• /test-windows-conformance: to trigger windows conformance tests.
• /skip-windows-conformance: to skip windows conformance tests.
• /test-all: to trigger all tests (except whole conformance).
• /skip-all: to skip all tests (except whole conformance).

These commands can only be run by members of the vmware-tanzu organization.

[tnqn]

LGTM

[antoninbas]

/test-all

[antoninbas]

/test-windows-conformance
/test-windows-networkpolicy

[antoninbas]

Independent failure in jenkins-windows-networkpolicy , merging now

[antoninbas]

/test-e2e

[lzhecheng]

/test-e2e