[FIX] odoo-shippable: Active the virtual environment in the top of the .bashrc

Active the virtual environment in the top of the file .bashrc because the file .bashrc contains the follow sentence

# If not running interactively, don't do anything
[ -z "$PS1" ] && return

and when the gitlab-ci run using this imagen the virtual environment is not load as should be

This change will enable the possibility to use the environment variable TRAVIS_PYTHON_VERSION on the build of gitlab-ci