add missing ifndef FOLLY_NO_CONFIG around include in folly/compression/Counters.cpp
add missing ifndef FOLLY_NO_CONFIG around include in folly/compression/Counters.cpp

Summary: Needed to update folly in the open source build of HHVM.

Reviewed By: yfeldblum

Differential Revision: D6913772

fbshipit-source-id: 50e540fe30651c991dc198ede66d4816a85f68db

rklabs/folly,rklabs/folly,facebook/folly,facebook/folly,rklabs/folly,facebook/folly,rklabs/folly,facebook/folly,rklabs/folly,facebook/folly