RFR: Handle trailing blank lines in commit message

[Robin Westberg]

This change ensures that a commit message ending with a blank line does not generate an exception.

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Commit messages:
 - Handle trailing blank lines in commit message

Changes: https://git.openjdk.java.net/skara/pull/959/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=959&range=00
  Stats: 27 lines in 2 files changed: 22 ins; 5 del; 0 mod
  Patch: https://git.openjdk.java.net/skara/pull/959.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/959/head:pull/959

PR: https://git.openjdk.java.net/skara/pull/959