[OTS] sanitizer incorrectly rejects fonts with optical size feature ('size')

Fix a wrong calculation of FeatureTable length.
The patch is provided by jfkthame.

TEST=ran test_{un,}malicious_fonts.sh
BUG=104389


git-svn-id: http://ots.googlecode.com/svn/trunk@75 a4e77c2c-9104-11de-800e-5b313e0d2bf3
diff --git a/src/layout.cc b/src/layout.cc
index 8dea164..0482a27 100644
--- a/src/layout.cc
+++ b/src/layout.cc
@@ -147,7 +147,7 @@
   }
 
   const unsigned feature_table_end =
-      2 * static_cast<unsigned>(num_lookups) + 4;
+      2 * static_cast<unsigned>(lookup_count) + 4;
   if (feature_table_end > std::numeric_limits<uint16_t>::max()) {
     return OTS_FAILURE();
   }