[env] Remove unused file

env.yml

-name: bdt
-channels:
-- https://www.idiap.ch/software/bob/conda
-- defaults
-dependencies:
-- python=3.6
-- bob.buildout
-- click
-- click-plugins
-- conda-build
-- ipdb
-- sphinx
-- sphinx_rtd_theme
-- pip
-- pytz
-- python-dateutil
-- chardet
-- idna
-- requests
-- urllib3
-- pip:
-  - python-gitlab