Fix fun Travis DCO check YAML parsing issues (especially with commit messages that start with any kind of whitespace, like this one intentionally does)

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #3848 from tianon/fix-yaml-space-parsing

 Fix fun Travis DCO check YAML parsing issues (especially with commit messages that start with any kind of whitespace, like this one intentionally does)