GitInfoParser incompatible with BitRise git-clone step

[roubertedgar]

On BitRise the git-clone step offers an option to Merge the Pull Request source branch into destination or Checkout merged PR state in newer versions to check merge issues. When activated, this option generates an issue in the GitInfoParser, as it always gets the commit info for the HEAD.

    val rev = repo.resolve("HEAD")
    val commit = RevWalk(repo).parseCommit(rev)

If the merge option is enabled, the HEAD will point to the merged local commit state, not the commit that generated the build itself causing the following issues:

• Unable to see the commit author in coveralls
• Unable to see the commit message in coveralls
• Unable to open changed files as the commit hash is not valid (it only exists on BitRise)

Proposal

Have the possibility to use the coveralls env var CI_COMMIT_ID instead of just using HEAD