use llvm35's scan-build for static analysis on OSX
use llvm35's scan-build for static analysis on OSX

ethereum/ethereum-buildbot,vaporry/ethereum-buildbot,chfast/ethereum-buildbot,vaporry/ethereum-buildbot,vaporry/ethereum-buildbot,ethereum/ethereum-buildbot,chfast/ethereum-buildbot,chfast/ethereum-buildbot,ethereum/ethereum-buildbot