Add StringKeyedMap/Set.h to OSS build

Summary: Eden uses this and won't build with OSS folly without it.

Reviewed By: Orvid

Differential Revision: D4132103

fbshipit-source-id: 68d6c7dc642a7401eca60b0713db9f90cc11ced1

folly/Makefile.am

@@ -131,6 +131,8 @@ nobase_follyinclude_HEADERS = \
 	experimental/symbolizer/Symbolizer.h \
 	experimental/Select64.h \
 	experimental/StringKeyedCommon.h \
+	experimental/StringKeyedMap.h \
+	experimental/StringKeyedSet.h \
 	experimental/StringKeyedUnorderedMap.h \
 	experimental/StringKeyedUnorderedSet.h \
 	experimental/TestUtil.h \