tests: fixes eject/umount on SPARC

Since SPARC is using 'sun' partition table by default, make test not to
assume that disk has 'dos' partition table, so write 'dos' partition
table on disk, before proceeding any further.

Signed-off-by: Anatoly Pugachev <matorola@gmail.com>

tests/ts/eject/umount

@@ -35,6 +35,7 @@ function init_partitions {
 
 	ts_log "Create partitions"
 	$TS_CMD_FDISK $dev >> /dev/null 2>&1 <<EOF
+o
 n
 p
 1