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

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

src/hb-ot-shape-complex-khmer.cc

diff --git a/src/hb-ot-shape-complex-khmer.cc b/src/hb-ot-shape-complex-khmer.cc
index 264515e..0b5b50a 100644
--- a/src/hb-ot-shape-complex-khmer.cc
+++ b/src/hb-ot-shape-complex-khmer.cc
@@ -24,8 +24,8 @@
  * Google Author(s): Behdad Esfahbod
  */
 
-#include "hb-ot-shape-complex-khmer-private.hh"
-#include "hb-ot-layout-private.hh"
+#include "hb-ot-shape-complex-khmer.hh"
+#include "hb-ot-layout.hh"
 
 
 /*