smartd: close file descriptors of SCSI device if not SMART capable

added new temperature attribute (231, temperature)
smartd: now open ATA disks using O_RDONLY
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git-svn-id: https://smartmontools.svn.sourceforge.net/svnroot/smartmontools/trunk@111 4ea69e1a-61f1-4043-bf83-b5c94c648137