Replace filter() calls with list comprehensions

In Python 3, filter() returns an iterator.
Use list comprehensions instead.

Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Jan Cholasta <jcholast@redhat.com>

ipapython/setup.py.in

@@ -62,7 +62,7 @@ def setup_package():
             description = DOCLINES[0],
             long_description = "\n".join(DOCLINES[2:]),
             download_url = "http://www.freeipa.org/page/Downloads",
-            classifiers=filter(None, CLASSIFIERS.split('\n')),
+            classifiers=[line for line in CLASSIFIERS.split('\n') if line],
             platforms = ["Linux", "Solaris", "Unix"],
             package_dir = {'ipapython': ''},
             packages = ["ipapython",