[PATCH] Expose the name of the checker producing each diagnostic message.

[Jordan Rose]

  I'm sorry, but again, it's not okay to output a random name or all of the names associated with a checker. Each diagnostic a checker prints has to do with a //specific// user-visible checker name, not just any old name. It's fine to do something like this for checkers that only implement one set of checks, but for MallocChecker we need to actually get this right or not do it at all.

http://llvm-reviews.chandlerc.com/D2557