Add __attribute__((unused)) for unused parameters

Summary:
GCC 4.8 is more picky about unused parameters

Change-Id: Ib3a9f3e8c54d11f4f246207d68c38764d5cad9f9

Test Plan: Working fine with my builds, someone else should test though

Reviewers: randall.rushing, Mustaavalkosta, rlasalle15, Roach, synergy

Reviewed By: synergy

Differential Revision: http://review.codefirex.com/D202