RFR: Decrease log level for harmless warning

[Robin Westberg]

Decrease log level of a warning that can be ignored.

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Commit messages:
 - Decrease log level

Changes: https://git.openjdk.java.net/skara/pull/1072/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1072&range=00
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/1072.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1072/head:pull/1072

PR: https://git.openjdk.java.net/skara/pull/1072