Switch from -defs.h pattern

Summary: [Folly] Switch from `-defs.h` pattern to `-inl.h` pattern in `folly/stats/` since `extern template` doing shallow instantiation rather than deep instantiation makes this pattern difficult.

Reviewed By: chadaustin

Differential Revision: D16761319

fbshipit-source-id: 1760bf53b09791bebf996064c0d1fcc3babf43d2

openr/common/StepDetector.h

@@ -11,8 +11,7 @@
 #include <functional>
 #include <stdexcept>
 
-#include <folly/stats/BucketedTimeSeries-defs.h>
-#include <folly/stats/BucketedTimeSeries.h> // Order of include is IMP
+#include <folly/stats/BucketedTimeSeries.h>
 
 namespace openr {