[Piglit] Issues with xz compression support using the xz command line utility

[Michel Dänzer]

The first problem is that the compressed filename ends up as
results.json..xz instead of results.json.xz. The extra dot breaks piglit
summary:

Warning: A python exception that should have been handled was not. This is bug and should be reported.
BUG: No module supports file extensions "."

The uncompressed file already has the extraneous dot at the end of its
name.


Another problem is that -f isn't passed to the xz command line utility,
so overwriting existing results fails at the compression stage at the
end:

xz: /home/daenzer/src/piglit-git/piglit/results/quick_cl.20150722-baseline/results.json..xz: File exists
Warning: A python exception that should have been handled was not. This is bug and should be reported.
BUG: Command '['xz', '--compress', '-9', '/home/daenzer/src/piglit-git/piglit/results/quick_cl.20150722-baseline/results.json.']' returned non-zero exit status 1



-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer