remove trap debugging (its already built into the knapsack_pro gem)

spec/spec_helper.rb

@@ -254,24 +254,3 @@
   Kernel.srand config.seed
 =end
 end
-
-# Debugging: RSpec hangs / freezes
-# https://github.com/rspec/rspec-rails/issues/1353#issuecomment-93173691
-puts "rspec pid: #{Process.pid}"
-
-trap 'USR1' do
-  threads = Thread.list
-
-  puts
-  puts "=" * 80
-  puts "Received USR1 signal; printing all #{threads.count} thread backtraces."
-
-  threads.each do |thr|
-    description = thr == Thread.main ? "Main thread" : thr.inspect
-    puts
-    puts "#{description} backtrace: "
-    puts thr.backtrace.join("\n")
-  end
-
-  puts "=" * 80
-end