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

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

src/hb-map.cc

diff --git a/src/hb-map.cc b/src/hb-map.cc
index 138a856..225f37b 100644
--- a/src/hb-map.cc
+++ b/src/hb-map.cc
@@ -24,7 +24,7 @@
  * Google Author(s): Behdad Esfahbod
  */
 
-#include "hb-map-private.hh"
+#include "hb-map.hh"
 
 
 /* Public API */