mavlink: 2014.12.12-0 in 'hydro/distribution.yaml' [bloom]

Increasing version of package(s) in repository `mavlink` to `2014.12.12-0`:

- upstream repository: https://github.com/mavlink/mavlink.git
- release repository: https://github.com/mavlink/mavlink-gbp-release.git
- distro file: `hydro/distribution.yaml`
- bloom version: `0.5.15`
- previous version for package: `2014.11.11-2`