Don't show duplicate builds in "Related builds"

Since a build may be a member of multiple jobset evaluations, we need
to do a "select distinct" here.  But maybe we should only show builds
from a single evaluation (e.g. the most recent), since showing builds
from several may be confusing.

src/lib/Hydra/Controller/Build.pm

@@ -83,7 +83,7 @@ sub view_build : Chained('build') PathPart('') Args(0) {
 
     my $r = joinWithResultInfo( $c, $c->model('DB::Builds'))->search(
         { eval => { -in => $build->jobsetevalmembers->get_column('eval')->as_query } }
-      , { join => 'jobsetevalmembers', order_by => [ 'project', 'jobset', 'job'] }
+      , { join => 'jobsetevalmembers', order_by => [ 'project', 'jobset', 'job'], distinct => 1 }
       );
     if ($r->count <= 100) {
         $c->stash->{relatedbuilds} = [$r->all];

src/root/build.tt

@@ -437,6 +437,7 @@
 	<div id="tabs-relatedbuilds">
 		
 		<h2>Related builds</h2>
+		<p>The following builds are part of the same jobset evaluation that produced this build.</p>
 		[% INCLUDE renderBuildList builds=relatedbuilds%]
 	</div>
         [% END %]