Better message for migrating global projects

lib/tasks/migrate/migrate_global_projects.rake

 desc "GITLAB | Migrate Global Projects to Namespaces"
 task migrate_global_projects: :environment do
-  puts "This will move all projects without namespace to owner namespace"
+  found = Project.where(namespace_id: nil).count
+  if found > 0
+    puts "Global namespace is deprecated. We found #{found} projects stored in global namespace".yellow
+    puts "You may abort this task and move them to group/user namespaces manually."
+    puts "If you want us to move this projects under owner namespaces then continue"
     ask_to_continue
+  else
+    puts "No global projects found. Proceed with update.".green
+  end
 
   Project.where(namespace_id: nil).find_each(batch_size: 20) do |project|
     begin