Bug #19393: Federated tests fail on Windows under pushbuild

  Supplying --skip-rpl to mysql-test-run.pl would always disable the
  slaves, but those slaves may still be needed for the federated tests.
  Now we only disable the slaves when they are not used by any of the
  tests.

mysql-test/mysql-test-run.pl

@@ -258,6 +258,7 @@ our $opt_result_ext;
 
 our $opt_skip;
 our $opt_skip_rpl;
+our $use_slaves;
 our $opt_skip_test;
 our $opt_skip_im;
 
@@ -407,16 +408,15 @@ sub main () {
     my $tests= collect_test_cases($opt_suite);
 
     # Turn off NDB and other similar options if no tests use it
-    my ($need_ndbcluster,$need_im,$need_slave);
+    my ($need_ndbcluster,$need_im);
     foreach my $test (@$tests)
     {
       $need_ndbcluster||= $test->{ndb_test};
       $need_im||= $test->{component_id} eq 'im';
-      $need_slave||= $test->{slave_num};
+      $use_slaves||= $test->{slave_num};
     }
     $opt_with_ndbcluster= 0 unless $need_ndbcluster;
     $opt_skip_im= 1 unless $need_im;
-    $opt_skip_rpl= 1 unless $need_slave;
 
     snapshot_setup();
     initialize_servers();
@@ -981,7 +981,7 @@ sub snapshot_setup () {
     $master->[0]->{'path_myddir'},
     $master->[1]->{'path_myddir'});
 
-  unless ($opt_skip_rpl)
+  if ($use_slaves)
   {
     push @data_dir_lst, ($slave->[0]->{'path_myddir'},
                          $slave->[1]->{'path_myddir'},
@@ -1636,7 +1636,7 @@ sub mysql_install_db () {
   install_db('master', $master->[0]->{'path_myddir'});
   install_db('master', $master->[1]->{'path_myddir'});
 
-  if ( ! $opt_skip_rpl )
+  if ( $use_slaves )
   {
     install_db('slave',  $slave->[0]->{'path_myddir'});
     install_db('slave',  $slave->[1]->{'path_myddir'});