Rely on value_ref_ptr::operator->

Simon pointed out some spots were doing val.get()->mumble, where val
is a value_ref_ptr.  These were introduced by the function-to-method
script, replacing older code that passed the result of .get() to a
function.

Now that value.h is using methods, we can instead rely on operator->.
This patch replaces all the newly-introduced instances of this.

Approved-By: Simon Marchi <simon.marchi@efficios.com>