Show the close description on the diff viewer page.
Show the close description on the diff viewer page.

The close description was only shown on the review request page,
not on the diff viewer page, despite showing the banner. This now
adds the close description there as well.

Fixes bug #2913

bkochendorfer/reviewboard,chipx86/reviewboard,1tush/reviewboard,KnowNo/reviewboard,KnowNo/reviewboard,sgallagher/reviewboard,davidt/reviewboard,chipx86/reviewboard,custode/reviewboard,bkochendorfer/reviewboard,reviewboard/reviewboard,1tush/reviewboard,brennie/reviewboard,reviewboard/reviewboard,1tush/reviewboard,1tush/reviewboard,bkochendorfer/reviewboard,custode/reviewboard,1tush/reviewboard,davidt/reviewboard,KnowNo/reviewboard,beol/reviewboard,reviewboard/reviewboard,beol/reviewboard,davidt/reviewboard,davidt/reviewboard,chipx86/reviewboard,chipx86/reviewboard,brennie/reviewboard,sgallagher/reviewboard,brennie/reviewboard,beol/reviewboard,bkochendorfer/reviewboard,sgallagher/reviewboard,brennie/reviewboard,custode/reviewboard,1tush/reviewboard,1tush/reviewboard,1tush/reviewboard,custode/reviewboard,1tush/reviewboard,beol/reviewboard,reviewboard/reviewboard,KnowNo/reviewboard,sgallagher/reviewboard