Bug#956903: clang-tidy-6.0: Depends on cruft package python-yaml

[Scott Kitterman]

Package: clang-tidy-6.0
Version: 1:6.0.1-14
Severity: serious

The clang-tidy-6.0 package depends on python-yaml, which is now NBS and
will be removed from Testing at some point.  I understand that llvm 6.0
is sticking around to support ghc, but is clang-tidy needed for that?
If that binary could be dropped it would help with moving the python2-rm
transition forward.

Scott K