Update Travis to LLVM 3.9 to fix CI
Update Travis to LLVM 3.9 to fix CI

surround-io/oclgrind,surround-io/oclgrind,mpflanzer/Oclgrind,mpflanzer/Oclgrind,mpflanzer/Oclgrind,surround-io/oclgrind,mpflanzer/Oclgrind,surround-io/oclgrind