Fix over-reach of previous commit

Return getTrustedPath() method to SHAMap.

Return std::c/ref() uses to std::bind() calls.  Uses of
std::c/ref() tell bind() what it doesn't need to to copy.
From page 491 of The C++ Standard Library 2nd Ed:

  Note that bind() internally copies passed arguments.  To
  let the function object use a reference to a passed argument
  use ref() or cref().

I'd messed that up.  Fortunately David caught me.