Do not use the syck YAML engine

A different solution for the problem described in #1383.

We started using the syck engine in some cases to solve a roblem that
a) we can't reproduce now
b) we can solve in another way

This is the other solution. To have special logic for empty YAML files.

The reason why we want to avoid syck is that it gets into encoding problems with the configuration of `Style/WordArray`, which contains a regular expression.