Merge pull request #201 from kojix2/kojix2-patch3

Reduce error messages when bundler is not found

Author: mrkn

lib/iruby/command.rb

@@ -104,7 +104,7 @@ def run_kernel
       Dir.chdir(working_dir) if working_dir
 
       require boot_file if boot_file
-      check_bundler {|e| IRuby.logger.warn "Could not load bundler: #{e.message}\n#{e.backtrace.join("\n")}" }
+      check_bundler {|e| IRuby.logger.warn "Could not load bundler: #{e.message}" }
 
       require 'iruby'
       Kernel.new(config_file).run