[NTG-context] spurious space before section heading but only in pdf mode

[Sanjoy Mahajan]

Hmm, I just tried that example on the live context and it came out
fine.  It also uses pdfetex 1.21, but has a more recent (2006-04-07)
context.

-Sanjoy

`Never underestimate the evil of which men of power are capable.'
         --Bertrand Russell, _War Crimes in Vietnam_, chapter 1.