svg_element: minor debug output fix.
svg_element: minor debug output fix.

gjtorikian/lasem,janmarthedal/mathml2svg,wavewave/lasem,gjtorikian/lasem,gjtorikian/lasem,janmarthedal/mathml2svg,janmarthedal/mathml2svg,wavewave/lasem,gjtorikian/lasem,janmarthedal/mathml2svg,wavewave/lasem,wavewave/lasem