Fix undefined local variable or method `klass_name' for Resque::Scheduler:Class
Allowing for conditional disabling of test redis server

so that we don't error out on Travis due to redis server shutdown
issues, for example, as happened for #309.

Conflicts:
	test/support/redis_instance.rb
	test/test_helper.rb
Backporting the test redis instance stuff to v1.9-stable
Merge pull request #317 from meatballhat/radsaq-fix_klass_name_error

Radsaq fix klass name error