[1.7.x] Correct oversight in trove classifiers, as this branch is now beta status.

setup.py

@@ -49,7 +49,7 @@ setup(
     ]},
     zip_safe=False,
     classifiers=[
-        'Development Status :: 3 - Alpha',
+        'Development Status :: 4 - Beta',
         'Environment :: Web Environment',
         'Framework :: Django',
         'Intended Audience :: Developers',