Fix little bool++ usage that clang caught.
Fix little bool++ usage that clang caught.

h3rb/openshadinglanguage,qdtk/openshadinglanguage,qdtk/openshadinglanguage,h3rb/openshadinglanguage,tectronics/openshadinglanguage,qdtk/openshadinglanguage,tectronics/openshadinglanguage,qdtk/openshadinglanguage,h3rb/openshadinglanguage,tectronics/openshadinglanguage,h3rb/openshadinglanguage,tectronics/openshadinglanguage