Fixed some missing permission conditions

app/views/groups/_settings_head.html.haml

+- can_admin_group = can?(current_user, :admin_group, @group)
+- can_edit = can?(current_user, :admin_group, @group)
 = content_for :sub_nav do
   .scrolling-tabs-container.sub-nav-scroll
     = render 'shared/nav_scroll'
@@ -8,6 +10,7 @@
             %span
               Projects
 
+        - if can_edit && can_admin_group
           = nav_link(path: 'groups#edit') do
             = link_to edit_group_path(@group), title: 'Edit Group' do
               %span

app/views/layouts/nav/_group.html.haml

 - can_admin_group = can?(current_user, :admin_group, @group)
-- can_edit = can?(current_user, :admin_group, @group)
 .scrolling-tabs-container{ class: nav_control_class }
   .fade-left
     = icon('angle-left')
@@ -26,8 +25,7 @@
       = link_to group_group_members_path(@group), title: 'Members' do
         %span
           Members
-    - if current_user
-      - if can_admin_group || can_edit
+    - if current_user && can_admin_group
       = nav_link(path: %w[groups#projects groups#edit]) do
         = link_to projects_group_path(@group), title: 'Settings' do
           %span