Prefer newer llvm/clang versions in debian packaging

debian/control

@@ -4,10 +4,10 @@ Section: misc
 Priority: optional
 Standards-Version: 3.9.5
 Build-Depends: debhelper (>= 9), cmake,
- libllvm3.7 [!arm64] | libllvm3.8 [!arm64] | libllvm6.0 | libllvm8.0 | libllvm9,
- llvm-3.7-dev [!arm64] | llvm-3.8-dev [!arm64] | llvm-6.0-dev | llvm-8.0-dev | llvm-9-dev,
- libclang-3.7-dev [!arm64] | libclang-3.8-dev [!arm64] | libclang-6.0-dev | libclang-8.0-dev | libclang-9-dev,
- clang-format | clang-format-3.7 [!arm64] | clang-format-3.8 [!arm64] | clang-format-6.0 | clang-format-8.0 | clang-format-9,
+ libllvm9 | libllvm8.0 | libllvm6.0 | libllvm3.8 [!arm64] | libllvm3.7 [!arm64],
+ llvm-9-dev | llvm-8.0-dev | llvm-6.0-dev | llvm-3.8-dev [!arm64] | llvm-3.7-dev [!arm64],
+ libclang-9-dev | libclang-8.0-dev | libclang-6.0-dev | libclang-3.8-dev [!arm64] | libclang-3.7-dev [!arm64],
+ clang-format-9 | clang-format-8.0 | clang-format-6.0 | clang-format-3.8 [!arm64] | clang-format-3.7 [!arm64] | clang-format,
  libelf-dev, bison, flex, libfl-dev, libedit-dev, zlib1g-dev, git,
  python (>= 2.7), python-netaddr, python-pyroute2 | python3-pyroute2, luajit,
  libluajit-5.1-dev, arping, inetutils-ping | iputils-ping, iperf, netperf,