Remove the Build menu from the top bar

It's now a dropdown menu in the tabs thingy, which subsumes the
"Reproduce locally" button.  This makes the actions in the menu a bit
more visible, IMHO.

src/lib/Hydra/Controller/Build.pm

@@ -443,9 +443,8 @@ sub restart : Chained('buildChain') PathPart Args(0) {
 
     requireProjectOwner($c, $build->project);
 
-    my $drvpath = $build->drvpath;
     error($c, "This build cannot be restarted.")
-        unless $build->finished && -f $drvpath;
+        unless $build->finished && -f $build->drvpath;
 
     restartBuild($c->model('DB')->schema, $build);