Addresses #5090 setup module was using path.is_file instead of path.isfile

lib/ansible/module_utils/basic.py

@@ -122,7 +122,7 @@ def get_distribution():
     if platform.system() == 'Linux':
         try:
             distribution = platform.linux_distribution()[0].capitalize()
-            if not distribution and os.path.is_file('/etc/system-release'):
+            if not distribution and os.path.isfile('/etc/system-release'):
                 distribution = platform.linux_distribution(supported_dists=['system'])[0].capitalize()
                 if 'Amazon' in distribution:
                     distribution = 'Amazon'