landings_controller.rb: remove unused /landing route.

Broken since PopularPostExplorer was removed in 7269ec0.

app/assets/stylesheets/specific/landing.css.scss

@@ -1,44 +0,0 @@
-div#c-landings {
-  div#a-show {
-    padding-top: 4em;
-    width: 960px;
-    margin: auto;
-
-    h1 {
-      text-align: center;
-      font-size: 4em;
-    }
-
-    p.slogan {
-      text-align: center;
-      font-size: 1.5em;
-      font-weight: bold;
-    }
-
-    div.column {
-      width: 480px;
-      vertical-align: top;
-      float: left;
-      background-color: #000;
-    }
-
-    div.landing-post {
-      overflow: hidden;
-    }
-
-    div.landing-post:hover img {
-      opacity: 0.25;
-    }
-
-    div.landing-post:hover div.data {
-      opacity: 1.0;
-    }
-
-    div.landing-post div.data {
-      position: absolute;
-      color: white;
-      padding: 5px;
-      cursor: pointer;
-    }
-  }
-}

app/controllers/landings_controller.rb

@@ -1,6 +0,0 @@
-class LandingsController < ApplicationController
-  def show
-    @explorer = PopularPostExplorer.new
-    render :layout => "blank"
-  end
-end

app/helpers/landings_helper.rb

@@ -1,2 +0,0 @@
-module LandingsHelper
-end

config/routes.rb

@@ -160,7 +160,6 @@ Rails.application.routes.draw do
     end
   end
   resources :jobs
-  resource :landing
   resources :mod_actions
   resources :news_updates
   resources :notes do