uncomment bitbucket-related code

[kfjahnke]

Having tested as best as I could that the bitbucket-related code works as intended, I propose this pull request to re-activate it.

[probonopd]

Thanks @kfjahnke, let's see how it goes.

[probonopd]

Running into issues again:
https://github.com/AppImage/appimage.github.io/actions/runs/6176528675/job/16765645722#step:5:1476

++ grep '^https://bitbucket.org///downloads/.*AppImage$' data/ubpm
+ BB_LINK=
worker.sh exited with a non-zero code: 1

[kfjahnke]

So the last output of the test before the error is
BB_LINK=
it is empty, which is correct for ubpm. So the test
if [ x"$BB_LINK" != x"" ]
should fail, processing should continue after the 'fi', but it looks like the test isn't reached at all.

I can't see how this should should produce the exit with code 1, but it's hard to see because the exit code '1' is used in several places. The only thing I do differently is that I don't pipe the grep's output into sed to replace https with http, because the RE I grep for does not catch http without the trailing 's'. Be that as it may, I'll follow the template of OBS_LINK to the letter, change the grep and add the pipe to sed, then we can try if that works. I'll open a new PR.

[kfjahnke]

One more thing before I push the PR: I had a look at the AppImage you used for testing (ubpm) and noticed that the source is using the vcs-browser tag in their metadata.xml. Is it possible that your test chokes on that? They might have updated their metadat.xml to the new spec, making your older version of appstream-cli which does not recognize that tag fail on the input. I still think there is nothing wrong with the bitbucket-related code, but I'll send the PR anyway.