Merge pull request #656 from asottile/patch-1

Correct `extras_require` for conditional install

Author: timothycrosley

setup.py

@@ -60,7 +60,7 @@ def run(self):
       packages=['isort'],
       install_requires=install_requires,
       python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
-      extra_requires={"python_version==1.7'": ['futures']},
+      extras_require={':python_version=="2.7"': ['futures']},
       cmdclass={'test': PyTest},
       keywords='Refactor, Python, Python2, Python3, Refactoring, Imports, Sort, Clean',
       classifiers=['Development Status :: 6 - Mature',