Prefix temp data dirs with the node name

This makes it easier to relate the temporary data dirs to each node in
a test script.

Author: Kyotaro Horiguchi
Reviewed-By: Craig Ringer, Alvaro Herrera

src/test/perl/PostgresNode.pm

@@ -115,7 +115,7 @@ sub new
 	my $self   = {
 		_port     => $pgport,
 		_host     => $pghost,
-		_basedir  => TestLib::tempdir,
+		_basedir  => TestLib::tempdir("data_" . $name),
 		_name     => $name,
 		_logfile  => "$TestLib::log_path/${testname}_${name}.log" };
 

src/test/perl/TestLib.pm

@@ -128,8 +128,10 @@ sub all_tests_passing
 #
 sub tempdir
 {
+	my ($prefix) = @_;
+	$prefix = "tmp_test" unless defined $prefix;
 	return File::Temp::tempdir(
-		'tmp_testXXXX',
+		$prefix . '_XXXX',
 		DIR     => $tmp_check,
 		CLEANUP => 1);
 }