BLD: fix sphinx version req

pip complained about the `()`

Author: tacaswell

setup.py

@@ -34,7 +34,7 @@
     author_email="pav@iki.fi",
     url="https://github.com/numpy/numpy/blob/master/doc/HOWTO_DOCUMENT.rst.txt",
     license="BSD",
-    install_requires=["sphinx (>= 1.0.1)"],
+    install_requires=["sphinx >= 1.0.1"],
     package_data={'numpydoc': ['tests/test_*.py']},
     test_suite = 'nose.collector',
     cmdclass={"sdist": sdist},