Prevent the search result timestamps from jumping after load.
Prevent the search result timestamps from jumping after load.

The search results template was setting absolute dates/times for the
review request results, which were then converted into
"<minutes|hours|days|months> ago". This caused an annoying jump in the
text. We now just use the timesince filter to get that correct starting
value.

Testing Done:
Did a search and saw the time-since values. Didn't see any jumps in text.

Reviewed at https://reviews.reviewboard.org/r/7069/

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