Merge branch 'new-mr-layout-fix' into 'master'

Fixed issue with new MR form layout

Currently it is all over the place:

![Screen_Shot_2016-04-20_at_14.59.48](/uploads/09c3dffc2138140e3b009ab2564f0aca/Screen_Shot_2016-04-20_at_14.59.48.png)

Now:

![Screen_Shot_2016-04-20_at_14.59.44](/uploads/ef5ba8b7393253ecb732c57ba37dd0cf/Screen_Shot_2016-04-20_at_14.59.44.png)

See merge request !3837

app/views/shared/issuable/_form.html.haml

@@ -75,6 +75,7 @@
     = f.label :label_ids, "Labels", class: 'control-label'
     .col-sm-10{ class: ('issuable-form-padding-top' if !has_labels) }
       - if has_labels
+        .issuable-form-select-holder
           = f.collection_select :label_ids, issuable.project.labels.all, :id, :name,
             { selected: issuable.label_ids }, multiple: true, class: 'select2', data: { placeholder: "Select labels" }
       - else
@@ -88,6 +89,7 @@
   .form-group
     = label_tag :move_to_project_id, 'Move', class: 'control-label'
     .col-sm-10
+      .issuable-form-select-holder
         - projects = project_options(issuable, current_user, ability: :admin_issue)
         = select_tag(:move_to_project_id, projects, include_blank: true,
                      class: 'select2', data: { placeholder: 'Select project' })
@@ -102,13 +104,15 @@
     .form-group
       = f.label :source_branch, class: 'control-label'
       .col-sm-10
+        .issuable-form-select-holder
           = f.select(:source_branch, [@merge_request.source_branch], { }, { class: 'source_branch select2 span2', disabled: true })
   .form-group
     = f.label :target_branch, class: 'control-label'
     .col-sm-10
+      .issuable-form-select-holder
         = f.select(:target_branch, @merge_request.target_branches, { include_blank: true }, { class: 'target_branch select2 span2', disabled: @merge_request.new_record?, data: {placeholder: "Select branch"} })
       - if @merge_request.new_record?
-        %p.help-block
+         
         = link_to 'Change branches', mr_change_branches_path(@merge_request)
 
 - is_footer = !(issuable.is_a?(MergeRequest) && issuable.new_record?)