RFR: Store the check expiration info in the metadata

[Robin Westberg]

Move the check expiration info into the metadata instead.

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Commit messages:
 - Store the check expiration info in the metadata

Changes: https://git.openjdk.java.net/skara/pull/864/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=864&range=00
  Stats: 295 lines in 8 files changed: 141 ins; 119 del; 35 mod
  Patch: https://git.openjdk.java.net/skara/pull/864.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/864/head:pull/864

PR: https://git.openjdk.java.net/skara/pull/864