[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
1 file changed