GLWXDriver2D: fix compilation error
From Paul Brissaud[1]: Apparently, wxGLCanvasX11::m_vi is now private, so use GetXVisualInfo() accessor instead. Resolves #22 [1].
[1]: https://sourceforge.net/p/crystal/tickets/22/
Authored by: sunshine 2015-07-12
Parent: [r40279]
Child: [r40281]