RFR: Always set commit_id and comments when adding review

[Erik Helin]

Hi all,

please review this small patch that ensures that we always set the fields
`commit_id` and `comments` when adding a review to a GitHub pull request.

Testing:
- Manual testing using `git pr approve`

Thanks,
Erik

-------------

Commits:
 - cc6c6ba8: Always set commit_id and comments when adding review

Changes: https://git.openjdk.java.net/skara/pull/418/files
 Webrev: https://webrevs.openjdk.java.net/skara/418/webrev.00
  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/skara/pull/418.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/418/head:pull/418

PR: https://git.openjdk.java.net/skara/pull/418