RFR: 1048: Missing integration comment causes mlbridge to throw exceptions

[Erik Joelsson]

This patch changes the mlbridge bot to stop throwing errors when it encounters a PR marked as integrated but without the integration comment (which contains the information about the commit hash needed for the email). Instead, it's just logged and no action is taken. When the comment is eventually added, the bot will run again and the email will be sent.

The ordering of actions from the PR bot must unfortunately be like it is, with the comment added last.

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Commit messages:
 - SKARA-1048

Changes: https://git.openjdk.java.net/skara/pull/1205/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1205&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-1048
  Stats: 13 lines in 2 files changed: 10 ins; 1 del; 2 mod
  Patch: https://git.openjdk.java.net/skara/pull/1205.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1205/head:pull/1205

PR: https://git.openjdk.java.net/skara/pull/1205