Remove unused include which breaks build after r210803

Tested with llvm 3.4 and trunk.

llvm-svn: 210825

Author: Jeroen Ketema

libclc/utils/prepare-builtins.cpp

@@ -9,7 +9,6 @@
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/system_error.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/ToolOutputFile.h"
 #include "llvm/Config/config.h"