Revert "lib: cpp: automake: ship thrift/numeric_cast.h"

This reverts commit 779deabf0e1fdefe4f6340546181ac9d81fcf670.
diff --git a/lib/cpp/Makefile.am b/lib/cpp/Makefile.am
index 7512ec5..c015b0d 100644
--- a/lib/cpp/Makefile.am
+++ b/lib/cpp/Makefile.am
@@ -133,7 +133,6 @@
 include_thriftdir = $(includedir)/thrift
 include_thrift_HEADERS = \
                          $(top_builddir)/config.h \
-                         src/thrift/numeric_cast.h \
                          src/thrift/thrift-config.h \
                          src/thrift/thrift_export.h \
                          src/thrift/TDispatchProcessor.h \