Rename hb-*private.hh to hb-*.hh

Sorry for the noise, downstream custom builders.  Please adjust.

src/hb-subset-glyf.cc

diff --git a/src/hb-subset-glyf.cc b/src/hb-subset-glyf.cc
index 36af3be..e335912 100644
--- a/src/hb-subset-glyf.cc
+++ b/src/hb-subset-glyf.cc
@@ -24,7 +24,7 @@
  * Google Author(s): Garret Rieger, Roderick Sheeter
  */
 
-#include "hb-open-type-private.hh"
+#include "hb-open-type.hh"
 #include "hb-ot-glyf-table.hh"
 #include "hb-set.h"
 #include "hb-subset-glyf.hh"