Modifications to MTR and mysqltest to improve feedback from the latter when

testcase checks are made.
      
MTR spawns mysqltest to run check-testcase test before and after each testcase 
it runs. It can also run check-warnings using mysqltest. Since it happened on PB 
that these checks hanged, this patch provides additional feedback to help 
investigating such failures:
      
- mysqltest is modified to give feedback about main steps in execution of a 
testcase if run in verbose mode (including connection to the server),
     
- MTR is modified to run mysqltest in verbose mode when doing check-testcase or 
check-warnings. The diagnostic output from mysqltest is preserved so that it is 
saved upon test failure.

client/mysqltest.cc:
  Add verbose messages informing about main steps in execution of a testcase.
mysql-test/mysql-test-run.pl:
  - When doing check-testcase or check-warnings run mysqltest in verbose mode.
  - Do not delete the mysqltest's error log if errors are detected during these

client/mysqltest.cc

@@ -4647,6 +4647,10 @@ void safe_connect(MYSQL* mysql, const char *name, const char *host,
   int failed_attempts= 0;
 
   DBUG_ENTER("safe_connect");
+
+  verbose_msg("Connecting to server %s:%d (socket %s) as '%s'"
+              ", connection '%s', attempt %d ...", 
+              host, port, sock, user, name, failed_attempts);
   while(!mysql_real_connect(mysql, host,user, pass, db, port, sock,
                             CLIENT_MULTI_STATEMENTS | CLIENT_REMEMBER_OPTIONS))
   {
@@ -4678,6 +4682,7 @@ void safe_connect(MYSQL* mysql, const char *name, const char *host,
     }
     failed_attempts++;
   }
+  verbose_msg("... Connected.");
   DBUG_VOID_RETURN;
 }
 
@@ -7511,8 +7516,12 @@ int main(int argc, char **argv)
   parse_args(argc, argv);
 
   log_file.open(opt_logdir, result_file_name, ".log");
+  verbose_msg("Logging to '%s'.", log_file.file_name());
   if (opt_mark_progress)
+  {
     progress_file.open(opt_logdir, result_file_name, ".progress");
+    verbose_msg("Tracing progress in '%s'.", progress_file.file_name());
+  }
 
   var_set_int("$PS_PROTOCOL", ps_protocol);
   var_set_int("$SP_PROTOCOL", sp_protocol);
@@ -7521,6 +7530,8 @@ int main(int argc, char **argv)
 
   DBUG_PRINT("info",("result_file: '%s'",
                      result_file_name ? result_file_name : ""));
+  verbose_msg("Results saved in '%s'.", 
+              result_file_name ? result_file_name : "");
   if (mysql_server_init(embedded_server_arg_count,
 			embedded_server_args,
 			(char**) embedded_server_groups))
@@ -7591,6 +7602,7 @@ int main(int argc, char **argv)
     open_file(opt_include);
   }
 
+  verbose_msg("Start processing test commands from '%s' ...", cur_file->file_name);
   while (!read_command(&command) && !abort_flag)
   {
     int current_line_inc = 1, processed = 0;
@@ -7908,6 +7920,7 @@ int main(int argc, char **argv)
   log_file.close();
 
   start_lineno= 0;
+  verbose_msg("... Done processing test commands.");
 
   if (parsing_disabled)
     die("Test ended with parsing disabled");
@@ -7958,6 +7971,7 @@ int main(int argc, char **argv)
   if (!command_executed && result_file_name)
     die("No queries executed but result file found!");
 
+  verbose_msg("Test has succeeded!");
   timer_output();
   /* Yes, if we got this far the test has suceeded! Sakila smiles */
   cleanup_and_exit(0);

mysql-test/mysql-test-run.pl

@@ -2874,9 +2874,6 @@ test case was executed:\n";
 	  $result= 2;
 	}
 
-	# Remove the .err file the check generated
-	unlink($err_file);
-
 	# Remove the .result file the check generated
 	unlink("$base_file.result");
 
@@ -3494,6 +3491,7 @@ sub start_check_warnings ($$) {
 
   mtr_add_arg($args, "--skip-safemalloc");
   mtr_add_arg($args, "--test-file=%s", "include/check-warnings.test");
+  mtr_add_arg($args, "--verbose");
 
   if ( $opt_embedded_server )
   {
@@ -3583,10 +3581,9 @@ sub check_warnings ($) {
 
 	if ( $res == 62 ) {
 	  # Test case was ok and called "skip"
-	  ;
-	}
 	  # Remove the .err file the check generated
 	  unlink($err_file);
+	}
 
 	if ( keys(%started) == 0){
 	  # All checks completed
@@ -3608,8 +3605,6 @@ sub check_warnings ($) {
 
 	$result= 2;
       }
-      # Remove the .err file the check generated
-      unlink($err_file);
     }
     elsif ( $proc eq $timeout_proc ) {
       $tinfo->{comment}.= "Timeout $timeout_proc for ".
@@ -4493,6 +4488,7 @@ sub start_check_testcase ($$$) {
 
   mtr_add_arg($args, "--result-file=%s", "$opt_vardir/tmp/$name.result");
   mtr_add_arg($args, "--test-file=%s", "include/check-testcase.test");
+  mtr_add_arg($args, "--verbose");
 
   if ( $mode eq "before" )
   {
@@ -4664,7 +4660,6 @@ sub start_mysqltest ($) {
     debugger_arguments(\$args, \$exe, "client");
   }
 
-
   my $proc= My::SafeProcess->new
     (
      name          => "mysqltest",