genmsg: 0.4.25-0 in 'hydro/distribution.yaml' [bloom]

Increasing version of package(s) in repository `genmsg` to `0.4.25-0`:

- distro file: `hydro/distribution.yaml`
- bloom version: `0.5.1`
- previous version for package: `0.4.24-0`

## genmsg

```
* remove usage of debug_message() (#40 <https://github.com/ros/genmsg/issues/40>)
* revert "python 3 compatibility" (introduced in 0.4.24)
```