Remove the people link from the Admin menu

Its not implemented, and won't be anytime soon.  Better to just remove
the link for now, we have other items under the Admin menu that users
can access and make use of (Groups, Projects).

Signed-off-by: Shawn O. Pearce <sop@google.com>

appjar/src/main/java/com/google/gerrit/client/Gerrit.java

@@ -308,7 +308,6 @@ public class Gerrit implements EntryPoint {
 
     if (signedIn) {
       m = new MenuBar(true);
-      addLink(m, C.menuPeople(), Link.ADMIN_PEOPLE);
       addLink(m, C.menuGroups(), Link.ADMIN_GROUPS);
       addLink(m, C.menuProjects(), Link.ADMIN_PROJECTS);
       menuBar.addItem(C.menuAdmin(), m);