Fatal Error: undefined function flag_tracker_get_tracker_flag() on the 'manage e-mail notifications for issues' page

Related Issues

Original bug report: #1808156: D7 Upgrade QA Bug: Project Issue Queue - Fatal Error on 'manage e-mail notifications for issues' Page
Possibly related to? #1560012: Port per-user issue notification email functionality to D7

Example URL(s)

(A) http://drupal.org/project/issues/subscribe-mail/views
(B) http://git7site.devdrupal.org/project/issues/subscribe-mail/views

Steps To Reproduce

1. Visit the (B) URL to see the fatal error.

Expected Result (what I should have seen)

I expected to see the page Manage e-mail notifications for Views issues, where I can select my e-mail notification settings.

Bug Report (what I actually saw)

Instead, I get a: Fatal error: Call to undefined function flag_tracker_get_tracker_flag() in /var/www/git-dev.drupal.org/htdocs/sites/all/modules/project_issue/project_issue.module on line 1921

Annotated Screenshot(s)