Log Message:
Updated p5-autovivification to 0.17.

0.17    2017-07-31 17:15 UTC
        + Chg : A large chunk of boilerplate XS code, which is also used in
                other XS modules, has been factored out of the main .xs file
                to a collection of .h files in the xsh subdirectory.
        + Fix : The new optimization in perl 5.27.3 for scalar(keys(%$hashref))
                is now correcty supported.