Fix build to work with older harfbuzz versions.

Whee, seems hb has changed naming, with 0.9.11 it is spelled as
quoted. newer versions have a mapping in hb-deprecated.h ...

Change-Id: I425ded33e6b9928aadca9f6988437a021fcecbfb

vcl/generic/glyphs/gcach_layout.cxx

@@ -420,7 +420,7 @@ bool HbLayoutEngine::layout(ServerFontLayout& rLayout, ImplLayoutArgs& rArgs)
 
             static hb_unicode_funcs_t* pHbUnicodeFuncs = getUnicodeFuncs();
 
-            int nHbFlags = HB_BUFFER_FLAG_DEFAULT;
+            int nHbFlags = HB_BUFFER_FLAGS_DEFAULT;
             if (nMinRunPos == 0)
                 nHbFlags |= HB_BUFFER_FLAG_BOT; /* Beginning-of-text */
             if (nEndRunPos == rArgs.mnLength)