'Needs work' flag does not get reset after new push to pull-request

Issue Summary

'Needs work' flag does not get reset after new push to pull-request

Steps to Reproduce

1. A pull request reviewer marks a pull request as 'needs work'
2. Changes are pushed to the pull request branch

Expected Results

The 'needs work' flag should be removed (leaving the reviewer's status as 'unapproved')

Actual Results

In certain circumstances the 'needs work' flag is not removed

Workaround

A workaround is for any of the pull request reviewers to update their status (for example for the reviewer who still has the 'needs work' flag to remove it and add it again).