This option is now hidden both in the Tools menu and the Revision Control popup menu if you are using a source control provider that uses changelists (like e.g. Perforce). If you are using Git or Subversion (which don’t use changelists), it’s still visible.
You can get to the dialog by binding a keyboard shortcut to it in the Editor Preferences. But they apparently really want to do the changelist management yourself now.
Ciao, Daniel!