Log stderr of sdparm to file sdparm.error

There might be output on stderr like:

| root@grml ~ # sdparm --all --long  /dev/sda > /dev/null
| descriptor overflows reply len (12) for AT_LAST.1
| descriptor overflows reply len (12) for CDA_UNIT.1
| descriptor overflows reply len (12) for CDB_UNIT.1
| descriptor overflows reply len (12) for IOA_MODE.1

Ensure to log it to file "sdparm.error".

Closes: #10

grml-hwinfo

@@ -459,8 +459,10 @@ cd "${OUTDIR}" || exit 1
 
       if exectest sdparm ; then
         echo -e "sdparm --all --long /dev/${disk}:\n" >> sdparm
-        sdparm --all --long "/dev/$disk" >> ./sdparm
+        echo -e "stderr for sdparm --all --long /dev/${disk}:\n" >> sdparm.error
+        sdparm --all --long "/dev/$disk" >> ./sdparm 2>> ./sdparm.error
         echo -e "\n\n" >> sdparm
+        echo -e "\n\n" >> sdparm.error
       fi
 
       if exectest sg_inq ; then