Category version in install binary has ".qualifier"

[chanseokoh]

We always had the .qualifier part in our code, so this seems to be a post-effect of #2043.

[briandealwis]

Ah it's because of our post-signing product re-publishing step:

6. Run the Eclipse p2 Product Publisher to add our custom p2 metadata to the repository.

which manually invokes the p2 product publisher and thus doesn't benefit from the .qualifier expansion performed by Tycho.

Given that this is a release version, and the category IU is never actually downloaded to the user (and thus doesn't need to be unique), we should just update the release instructions to drop the .qualifier when updating the .product version.

This issue can go away whenever we're able to do signing as part of the build process.

[briandealwis]

Updated release doc.