In the current code NTLMv2 is used when talking about second generation
NTLM crypto algorithms. Most other publiations call this NTLM2, and use
NTLMv2 to describe a different crypto handshake that can be used by
either NTLM1 or NTLM2 crypto.

Mono calls GdipMeasureString with a height so large that rounding and
converting it to an integer gives a negative result.

This fixes a regression introduced by 10f58c14.