Set proper title when edit identity from admin area

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

app/views/admin/identities/edit.html.haml

-- page_title @user.name, "Users"
+- page_title "Edit", @identity.provider, "Identities", @user.name, "Users"
 %h3.page-title
   Edit identity for #{@user.name}
 %hr