[cleanup] Remove commented code in memory_manager as it is no longer valid.
[cleanup] Remove commented code in memory_manager as it is no longer valid.

mit-carbon/Graphite,fhijaz/Graphite,mit-carbon/Graphite-Cycle-Level,8l/Graphite,nkawahara/Graphite,nkawahara/Graphite,fhijaz/Graphite,fhijaz/Graphite,fhijaz/Graphite,mit-carbon/Graphite-Cycle-Level,mit-carbon/Graphite,8l/Graphite,victorisildur/Graphite,victorisildur/Graphite,victorisildur/Graphite,mit-carbon/Graphite,nkawahara/Graphite,mit-carbon/Graphite,victorisildur/Graphite,nkawahara/Graphite,mit-carbon/Graphite-Cycle-Level,8l/Graphite,8l/Graphite,mit-carbon/Graphite-Cycle-Level