license files should be listed relative to the src dir not recipe dir

See: https://conda.io/projects/conda-build/en/latest/resources/define-metadata.html#license-file

Our new bob conda recipes are wrong. The affected packages are:

bob.paper.deep_pix_bis_pad.icb2019/conda/meta.yaml
68:  license_file: ../COPYING

bob.buildout/conda/meta.yaml
58:  license_file: ../LICENSE

bob.devtools/bob/devtools/templates/conda/meta.yaml
59:  license_file: (% if license == 'gplv3' %)../COPYING(% else %)../LICENSE(% endif %)

and @tlaibacher packages (bob.ip.binseg, bob.db.drive, ...)

so the hacks created in: https://gitlab.idiap.ch/bob/bob.devtools/blob/1603b8f947567f86cd1ddc9b8f721bdb07f76060/bob/devtools/bootstrap.py#L49 are not needed.

Also, this issue: https://github.com/conda/conda-build/issues/3767 is not a real issue and should be closed.