Replace old logo with Nix/NixOS logo.

src/lib/Hydra/Controller/Root.pm

@@ -18,7 +18,7 @@ sub begin :Private {
     $c->stash->{version} = $ENV{"HYDRA_RELEASE"} || "<devel>";
     $c->stash->{nixVersion} = $ENV{"NIX_RELEASE"} || "<devel>";
     $c->stash->{curTime} = time;
-    $c->stash->{logo} = $ENV{"HYDRA_LOGO"} ? "/logo" : "/static/images/hydra.png" ;
+    $c->stash->{logo} = $ENV{"HYDRA_LOGO"} ? "/logo" : "/static/images/nixos-logo-only-hires.png" ;
     $c->stash->{tracker} = $ENV{"HYDRA_TRACKER"} ;
 
     if (scalar(@args) == 0 || $args[0] ne "static") {

src/root/static/css/hydra.css

@@ -5,7 +5,7 @@
 }
 
 .logo {
-    height: 20px;
+    height: 30px;
 }
 
 th {