Fix for video index issue related to https://webarchive.jira.com/browse/ARI-4082

Issue is that when user accesses https://wayback.archive-it.org/4280/20140625191711/http://www.maccabiusa.com/video/ (note trailing slash), the video that was captured at http://www.maccabiusa.com/video (note no trailing slash) is not found because the index contains the url without the trailing slash. This fix will detect if there is a trailing slash at the end of the search prefix and if so, remove it to do an additional query against the index without the trailing slash, adding any results to those that have already been found.

Not sure if the canonicalizer should have removed trailing slash from the prefix before the query??