Merge branch 'tag-page-updates' into 'master'

Fix styling of tag page

## What does this MR do?
Fixes tag page UI

## Screenshots (if relevant)
Before:    
![Screen_Shot_2016-07-18_at_3.09.28_PM](/uploads/575776fe7917321307baf2b8c2b34d75/Screen_Shot_2016-07-18_at_3.09.28_PM.png)
After:    
![Screen_Shot_2016-07-18_at_3.09.08_PM](/uploads/44f905318c01eb094989cb74bcd4c3c1/Screen_Shot_2016-07-18_at_3.09.08_PM.png)

See merge request !5334

app/assets/stylesheets/pages/tags.scss

+.tag-buttons {
+  line-height: 40px;
+
+  .btn:not(.dropdown-toggle) {
+    margin-left: 10px;
+  }
+}

app/views/projects/tags/show.html.haml

+- @no_container = true
 - page_title @tag.name, "Tags"
 = render "projects/commits/head"
 
-.row-content-block
-  .pull-right
+%div{ class: container_class }
+  .sub-header-block
+    .pull-right.tag-buttons
       - if can?(current_user, :push_code, @project)
-      = link_to edit_namespace_project_tag_release_path(@project.namespace, @project, @tag.name), class: 'btn-grouped btn has-tooltip', title: 'Edit release notes' do
+        = link_to edit_namespace_project_tag_release_path(@project.namespace, @project, @tag.name), class: 'btn has-tooltip', title: 'Edit release notes' do
           = icon("pencil")
-    = link_to namespace_project_tree_path(@project.namespace, @project, @tag.name), class: 'btn btn-grouped has-tooltip', title: 'Browse files' do
+      = link_to namespace_project_tree_path(@project.namespace, @project, @tag.name), class: 'btn has-tooltip', title: 'Browse files' do
         = icon('files-o')
-    = link_to namespace_project_commits_path(@project.namespace, @project, @tag.name), class: 'btn btn-grouped has-tooltip', title: 'Browse commits' do
+      = link_to namespace_project_commits_path(@project.namespace, @project, @tag.name), class: 'btn has-tooltip', title: 'Browse commits' do
         = icon('history')
       - if can? current_user, :download_code, @project
         = render 'projects/tags/download', ref: @tag.name, project: @project
@@ -16,6 +18,7 @@
         .pull-right
           = link_to namespace_project_tag_path(@project.namespace, @project, @tag.name), class: 'btn btn-remove remove-row grouped has-tooltip', title: "Delete tag", method: :delete, data: { confirm: "Deleting the '#{@tag.name}' tag cannot be undone. Are you sure?" } do
             %i.fa.fa-trash-o
+    .tag-info.append-bottom-10
       .title
         %span.item-title= @tag.name
       - if @commit
@@ -26,7 +29,7 @@
       %pre.body
         = strip_gpg_signature(@tag.message)
 
-.append-bottom-default.prepend-top-default
+  .append-bottom-default.prepend-top-default
     - if @release.description.present?
       .description
         .wiki