vps_start_custom(): fixup

In case VPS_PRESTART script failed, we just return an error,
no need to rollback anything yet.

This is a fix to commit 0807ef4.

Found by Coverity, CID 1271650, 1271651, 1271652.

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
1 file changed