RFR: Fix race condition in mailman cache test

[Robin Westberg]

Hi all,

Please review this small change that fixes a race condition in the mailman cache test.

Best regards,
Robin

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Commits:
 - 6e665956: Fix race condition in test

Changes: https://git.openjdk.java.net/skara/pull/358/files
 Webrev: https://webrevs.openjdk.java.net/skara/358/webrev.00
  Stats: 2 lines in 1 file changed: 1 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/skara/pull/358.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/358/head:pull/358

PR: https://git.openjdk.java.net/skara/pull/358