[pdal] First stab at Coverity Scan

[Howard Butler]

> On Nov 30, 2016, at 3:26 PM, Mateusz Loskot <mateusz at loskot.net> wrote:
> 
> Hi,
> 
> I've joined Andrew's efforst and I'm trying to configure Coverity Scan for PDAL.
> I have configured it for several projects, including libLAS and
> it generally is not a great deal of work.
> 
> However, with PDAL I'm hitting a wall.
> 
> I created new branch in PDAL/PDAL repo:
> 
> https://github.com/PDAL/PDAL/tree/coverity_scan
> 
> (Initially, I worked in mloskot/PDAL and I thought my problems
> might be due missing some secret configs on GitHub/Travis CI.)
> 
> The build is failing with the error:
> 
> docker: command not found
> 
> https://travis-ci.org/PDAL/PDAL/jobs/180215967
> 
> In .travis.yml, I haven't changed anything regarding docker.
> I only re-configured the build matrix a bit adding 3rd build for the Coverity.
> 
> I'm puzzled:
> Why Travis CI properly sets up the docker service for the builds of master,
> while it fails to do it for build based on coverity_scan branch?

Travis looks like it is not starting Docker for some reason. 

See https://travis-ci.org/PDAL/PDAL/jobs/180215967#L119

Others seem to have similar problems, but the path forward is not clear https://www.google.com/search?q=travis+docker+unrecognized+service&

Howard