dependency_links seems to be unable to work with git over ssh

Originally reported by: warrior2031 (Bitbucket: warrior2031, GitHub: warrior2031)

#!python

from setuptools import setup
import os
# os.system('pip install -e git+git@bitbucket.org:opticsdevelopment/serialization.git#egg=serialization')
setup(
    name='rest_framework',
    version='',
    packages=['base_tests', 'rest_framework', 'rest_framework.resources'],
    url='',
    license='',
    author='michael',
    author_email='warrior2031@mail.ru',
    description='',
    install_requires=[
        'ZODB',
        'pymongo',
        'zodbpickle'
    ],
    dependency_links=['git+git@bitbucket.org:opticsdevelopment/serialization.git#egg=serialization']
)

So this gives as output

#!python

Not found: git+git@bitbucket.org:opticsdevelopment/serialization.git#egg=serialization

However if I would uncomment third line then dependency would be installed succesfully.

I think of it as bug because documentation says

"VCS being used by prepending the URL with a certain prefix. Currently available are:

svn+URL for Subversion,
git+URL for Git, and
hg+URL for Mercurial"

And my url is in the form of git+URL right?

• Bitbucket: https://bitbucket.org/pypa/setuptools/issue/407

Start by reproducing the issue with the shown setup.py and its dependency_links value, then trace setuptools' handling of VCS URLs and SSH-style Git addresses. Confirm whether the git+git@bitbucket.org form is recognized as a dependency, and add coverage if the relevant test location can be identified.