rspec/rspec-core — pull request #923 by samphippen (2013-05-31 18:10:24+00:00)
Title: Remove #backtrace_clean_patterns.

This was deprecated a while ago. We've got deprecation specs in [2.99](https://github.com/rspec/rspec-core/blob/2-99-maintenance/spec/rspec/core/configuration_spec.rb#L1042).
This patch removes it.