tests: mkreiserfs only supports 4096 block size

Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

tests/util/grub-fs-tester.in

@@ -126,8 +126,10 @@ for LOGSECSIZE in $(range "$MINLOGSECSIZE" "$MAXLOGSECSIZE" 1); do
 	    MAXBLKSIZE=4096
 	    ;;
 	xreiserfs*)
-	    MINBLKSIZE=512
+	    # OS LIMITATION: mkreiserfs says block sizes smaller than 4 KiB are
-		# OS LIMITATION: 8192 isn't supported.
+	    # not supported and bails. Its been this way since at least 2014.
+	    MINBLKSIZE=4096
+	    # OS LIMITATION: 8192 isn't supported.
 	    MAXBLKSIZE=4096
 	    ;;
 	x"mdraid"*)