Remove icons from some buttons which already has text

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

app/views/groups/milestones/index.html.haml

@@ -6,7 +6,6 @@
   .nav-controls
     - if can?(current_user, :admin_milestones, @group)
       = link_to new_group_milestone_path(@group), class: "btn btn-new" do
-        = icon('plus')
         New Milestone
 
 .row-content-block

app/views/groups/projects.html.haml

@@ -7,7 +7,6 @@
     - if can? current_user, :admin_group, @group
       .controls
         = link_to new_project_path(namespace_id: @group.id), class: "btn btn-sm btn-success" do
-          = icon('plus')
           New Project
   %ul.well-list
     - @projects.each do |project|

app/views/shared/milestones/_summary.html.haml

@@ -26,7 +26,6 @@
     %span.pull-right.tab-issues-buttons
       - if project && can?(current_user, :create_issue, project)
         = link_to new_namespace_project_issue_path(project.namespace, project, issue: { milestone_id: milestone.id }), class: "btn  btn-grouped", title: "New Issue" do
-          %i.fa.fa-plus
           New Issue
       = link_to 'Browse Issues', milestones_browse_issuables_path(milestone, type: :issues), class: "btn btn-grouped"
     %span.pull-right.tab-merge-requests-buttons.hidden