fix string used for DVB DASH 2017 profile tests in MPD validator

[wschidol]

The codebase for the MPD validator contains tests against the DVB DASH 2017 profile. The tests however were never executed because the profile identifier string was erroneous. Fix this by using the correct identifier urn:dvb:dash:profile:dvb-dash:2017.

[wschidol]

The DASH/mpdvalidator/schematron directory contains the scripts create_val_schema.* which compile the schematron files into xslt (stored as output/val_schema.xsl). Should contributors to the schematron part of the codebase also, as part of the contribution, create and commit the output/val_schema.xsl file?
Also, run_samples.* validate all of the example files and output the results into output/result_ex*.xml. I assume that this affords some sort of regression testing by making sure that changes to the schematron source don't create regressions though I am not entirely sure how that testing is actually done. How should these regression tests be handled?

[dsilhavy]

@wschidol Thank you for the PR and your questions. We will discuss this internally and get back to you

[wschidol]

@wschidol Thank you for the PR and your questions. We will discuss this internally and get back to you

I am using a workflow now where I run all the samples before and after the change, and with a small in-house script create "digests" of the outputs. I then review any difference in the digests whether they are intentional or an unintended side effect.

[wschidol]

Any progress on this? Many other fixes are depending on this one, so I'd like to get it "out the door" so to speak.

[dsilhavy]

@wschidol Sorry for the delay, looks good to me, gonna merge this