Fix "No Summary" in dashboard with draft summaries.

The code in the dashboard that put in the italic "No Summary" for review
requests that had blank summaries wasn't ordered quite right, which meant that
if there was a draft with an empty summary present, the summary field would be
empty, but if it was merely a non-public review request, the summary field
would say "No Summary".

This change re-orders things to always override the displayed summary, whether
or not there's a draft.

Testing done:
Saw that my devserver with a bunch of draft/un-published review requests no
longer showed two different things based on the presence of a draft.

Reviewed at https://reviews.reviewboard.org/r/6136/
Fix post-commit review request creation on local sites.

The post-commit UI on the new review request page wasn't passing through the
local site prefix. This change fixes that.

Testing done:
Created a local site, and added a repo to it. Loaded /s/site/r/new/ and created
a post-commit review request.

Reviewed at https://reviews.reviewboard.org/r/6143/
Fix review request fields on Local Sites.

Review request fields were breaking on Local Sites. One case involved an
invalid variable name (review_request.local_site_name), and the other
never passed a LocalSite to local_site_reverse.

This fixes both cases.