Fix explore projects page UI

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/views/explore/projects/index.html.haml

@@ -6,7 +6,7 @@
 - else
   = render 'explore/head'
 
-.gray-content-block.clearfix
+.gray-content-block.clearfix.second-block
   = render 'filter'
 = render 'projects', projects: @projects
 = paginate @projects, theme: "gitlab"

app/views/explore/projects/starred.html.haml

@@ -7,7 +7,7 @@
   = render 'explore/head'
 
 .explore-trending-block
-  .gray-content-block
+  .gray-content-block.second-block
     .pull-right
       = render 'explore/projects/dropdown'
     .oneline

app/views/explore/projects/trending.html.haml

@@ -7,7 +7,7 @@
   = render 'explore/head'
 
 .explore-trending-block
-  .gray-content-block
+  .gray-content-block.second-block
     .pull-right
       = render 'explore/projects/dropdown'
     .oneline