Re-add line that was mistakenly removed alongside RPM support.

This reveals the need for bdist* tests.
diff --git a/Lib/packaging/command/bdist.py b/Lib/packaging/command/bdist.py
index 4338a97..e8c023d 100644
--- a/Lib/packaging/command/bdist.py
+++ b/Lib/packaging/command/bdist.py
@@ -128,6 +128,7 @@
         for i in range(len(self.formats)):
             cmd_name = commands[i]
             sub_cmd = self.get_reinitialized_command(cmd_name)
+            sub_cmd.format = self.formats[i]
 
             # passing the owner and group names for tar archiving
             if cmd_name == 'bdist_dumb':