fix command name

bin/account-manager.pl.in

@@ -65,7 +65,7 @@ my $db = AccountManager::DB->new();
 for ($action) {
     when ('add_account')    { add_account()    }
     when ('list_accounts')  { list_accounts()  }
-    when ('add_services')   { add_service()    }
+    when ('add_service')    { add_service()    }
     when ('list_services')  { list_services()  }
     when ('add_token')      { add_token()      }
     when ('get_token')      { get_token()      }