Drop '2' suffix from CS2, SBS2

Now that CS1 and SBS1 have been deleted, the suffixes of "2" on
a lot of classes is unncessary and confusing. Drop the suffix.

Change-Id: Icb8c4797f59f259601f4e436bd2f04a13a904bbc

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/Header.java

@@ -287,7 +287,7 @@ public class Header extends Composite {
       return k;
     } else {
       link.getElement().getStyle().setVisibility(Visibility.HIDDEN);
-      keys.add(new UpToChangeCommand2(patchSetId, 0, key));
+      keys.add(new UpToChangeCommand(patchSetId, 0, key));
       return null;
     }
   }