setuptools-git-version says "fatal" during package installation time

[miohtama]

setuptools-git-version tries to do something when a prepackaged package is being installed and fails with "fatal" error message. setuptools-git-version should not be active during package installation time, only during packaging time:

Collecting xxx-frontend==0.0.195+f649302 (from -r /srv/pyramid/xxx/requirements.txt (line 94))
  Downloading https://pypi.xxx.com/xxx/dev/+f/fb6/6278367bbf790/xxx_frontend-0.0.195+f649302.tar.gz (2.1MB)
    Complete output from command python setup.py egg_info:
    zip_safe flag not set; analyzing archive contents...

    Installed /tmp/pip-build-9e50qgrb/xxx-frontend/.eggs/setuptools_git_version-1.0.3-py3.5.egg
    fatal: Not a git repository (or any of the parent directories): .git
    running egg_info
    creating pip-egg-info/xxx_frontend.egg-info
    writing pip-egg-info/xxx_frontend.egg-info/PKG-INFO
    writing entry points to pip-egg-info/xxx_frontend.egg-info/entry_points.txt
    writing requirements to pip-egg-info/xxx_frontend.egg-info/requires.txt
    writing top-level names to pip-egg-info/xxx_frontend.egg-info/top_level.txt
    writing dependency_links to pip-egg-info/xxx_frontend.egg-info/dependency_links.txt
    writing manifest file 'pip-egg-info/xxx_frontend.egg-info/SOURCES.txt'
    warning: manifest_maker: standard file '-c' not found

    error: package directory 'xxx_frontend' does not exist

    ----------------------------------------

Whether "fatal" error message is relevant or not here is not clear, as it is probably sympton of a masked error or something. However if something is not fatal it should not appear in the installation messages.