git-svn: use SVN::Ra::get_dir2 when possible

This avoids the following failure with normal "get_dir" on newer
versions of SVN (tested with SVN 1.8.8-1ubuntu3.1):

  Incorrect parameters given: Could not convert '%ld' into a number

get_dir2 also has the potential to be more efficient by requesting
less data.

ref: <1414636504.45506.YahooMailBasic@web172304.mail.ir2.yahoo.com>
ref: <1414722617.89476.YahooMailBasic@web172305.mail.ir2.yahoo.com>

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>

perl/Git/SVN/Ra.pm

@@ -175,7 +175,17 @@ sub get_dir {
 		}
 	}
 	my $pool = SVN::Pool->new;
-	my ($d, undef, $props) = $self->SUPER::get_dir($dir, $r, $pool);
+	my ($d, undef, $props);
+
+	if (::compare_svn_version('1.4.0') >= 0) {
+		# n.b. in addition to being potentially more efficient,
+		# this works around what appears to be a bug in some
+		# SVN 1.8 versions
+		my $kind = 1; # SVN_DIRENT_KIND
+		($d, undef, $props) = $self->get_dir2($dir, $r, $kind, $pool);
+	} else {
+		($d, undef, $props) = $self->SUPER::get_dir($dir, $r, $pool);
+	}
 	my %dirents = map { $_ => { kind => $d->{$_}->kind } } keys %$d;
 	$pool->clear;
 	if ($r != $cache->{r}) {