Removes temporary rollout toggle ENABLE_SAML_CONFIG_SIGNAL_HANDLERS. The toggle was used to rollout a fix, and now the fix that uses the signal handlers is enabled by default. The only follow-up needed by anyone is to no longer set this toggle, which will no longer do anything.
common ------ This directory contains common code shared between LMS and CMS, such as Mako templates, CSS, and Coffescript.