Add clang-5.0 in precise to ubuntu-precise; resolves travis-ci/apt-package-whitelist#4033
Add clang-5.0 in precise to ubuntu-precise; resolves travis-ci/apt-package-whitelist#4033

Packages: clang-5.0 clang-format-5.0 clang-tidy-5.0 clang-5.0-doc libclang1-5.0 libclang1-5.0-dbg libclang-5.0-dev libclang-common-5.0-dev libfuzzer-5.0-dev python-clang-5.0 clang-5.0-examples libllvm5.0 libllvm5.0-dbg llvm-5.0 llvm-5.0-runtime llvm-5.0-dev llvm-5.0-tools libllvm-5.0-ocaml-dev llvm-5.0-doc llvm-5.0-examples lld-5.0 liblld-5.0 liblld-5.0-dbg liblld-5.0-dev lldb-5.0 liblldb-5.0 liblldb-5.0-dbg python-lldb-5.0 liblldb-5.0-dev

travis-ci/apt-package-whitelist,travis-ci/apt-package-whitelist