Summary: Dhruba can't compile on gcc4.8.1 so I'm moving temporarily back to 4.7.1 until we figure out what's wrong with 4.8. on his server.
Test Plan: It can compile on my devserver, but please 'arc patch' this diff and try compiling on your machine
Reviewers: dhruba, kailiu
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D14139
37eedfb8c1