Fix warnings in mysql-test-run.pl

mysql-test/lib/mtr_stress.pl:
  Remove duplicate definition of variable
mysql-test/mysql-test-run.pl:
  Fix spelling error
  Fix warning about uninitialised warning

mysql-test/lib/mtr_stress.pl

@@ -21,7 +21,6 @@ sub run_stress_test ()
 {
 
   my $args;
-  my $stress_basedir;
   my $stress_suitedir;
 
   mtr_report("Starting stress testing\n");

mysql-test/mysql-test-run.pl

@@ -1313,7 +1313,7 @@ sub kill_running_server () {
   {
     # Ensure that no old mysqld test servers are running
     # This is different from terminating processes we have
-    # started from ths run of the script, this is terminating
+    # started from this run of the script, this is terminating
     # leftovers from previous runs.
 
     mtr_report("Killing Possible Leftover Processes");
@@ -2752,7 +2752,7 @@ sub stop_masters () {
 
   my @args;
 
-  for ( my $idx; $idx < 2; $idx++ )
+  for ( my $idx= 0; $idx < 2; $idx++ )
   {
     # FIXME if we hit ^C before fully started, this test will prevent
     # the mysqld process from being killed
@@ -2783,7 +2783,7 @@ sub stop_slaves () {
 
   my @args;
 
-  for ( my $idx; $idx < 3; $idx++ )
+  for ( my $idx= 0; $idx < 3; $idx++ )
   {
     if ( $slave->[$idx]->{'pid'} )
     {