Another unreviewed build fix after r174475.

Don't try to insert a duplicated row into build_commits as it results in a database constraint error.

This has been caught by a test in /api/report. I don't know why I thought all tests were passing.

* public/include/report-processor.php:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@174494 268f45cc-cd09-0410-ab3c-d52691b4dbfc