Fix the rendering of the Manual Updates page.

A recent regression caused this page to render the wrong templates for
the update notifications. We now properly show the correct template.
Fix a missing endif tag for the Show SSH Public Key template.

When this change was backported to 1.7, an endif tag was left out. This
adds it back, and fixes indentation so that future mistakes won't be so
easily made.
Release Review Board 1.7.24.