[PATCH] Fix spelling

[Richard]

  I don't have commit access directly.  Not sure how to proceed here... can someone else commit for me?  I don't know yet if I'll be making frequent contributions, I'm mostly studying and learning code for the purposes of making my own tools and spotted this while reading some source code.

http://llvm-reviews.chandlerc.com/D1286

BRANCH
  default

ARCANIST PROJECT
  clang-tools-extra