Remove dead code from CVE-2012-0722 patch provided by Sajjad

That patch contains these lines:

 #define	NS_IN6ADDRSZ 16
 #define 	NS_INT16SZ = 2

As noted by Adam D. Barratt <adam@adam-barratt.org.uk>, the "=" in the
second is bogus.  This bug did not break the build because these
definitions were shadowed anyway.