Minor tweak to packaging tests.

When an option is changed on a command object, calling ensure_finalized
for a second time will not run finalize_options again, because
ensure_finalized is a no-op the second time.  By resetting the finalized
attribute, we can be sure that whatever computation takes place in
finalize_options will happen again.

(In test_command_clean, I removed two lines that were a no-op.)

Lib/packaging/tests/test_command_sdist.py

@@ -140,7 +140,7 @@ class SDistTestCase(support.TempdirManager,
 
         # now trying a tar then a gztar
         cmd.formats = ['tar', 'gztar']
-
+        cmd.finalized = False
         cmd.ensure_finalized()
         cmd.run()