[PATCH] fix a leak in CodeGenFunction::EmitSwitchStmt (detected by lsan)

[Chandler Carruth]

  Along the lines of Dave's comment, I'd prefer to change JumpDest to use an OwningPtr, and the places where we pass ownership to something else (an LLVM function, or whatever) use '.take()' to extract it safely.

http://llvm-reviews.chandlerc.com/D2472