GFS2: Fix ->show_options() for statfs slow

The ->show_options() function for GFS2 was not correctly displaying
the value when statfs slow in in use.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Reported-by: Milos Jakubicek <xjakub@fi.muni.cz>

fs/gfs2/super.c

@@ -1366,6 +1366,8 @@ static int gfs2_show_options(struct seq_file *s, struct dentry *root)
 	val = sdp->sd_tune.gt_statfs_quantum;
 	if (val != 30)
 		seq_printf(s, ",statfs_quantum=%d", val);
+	else if (sdp->sd_tune.gt_statfs_slow)
+		seq_puts(s, ",statfs_quantum=0");
 	val = sdp->sd_tune.gt_quota_quantum;
 	if (val != 60)
 		seq_printf(s, ",quota_quantum=%d", val);