Update sys.in to add missing "disk" flag.

It seems like only the short output of hwinfo --disk is provided to hardware.txt. I'd suggest we also add disk to the flags for the "complete" output.
That's especially useful when you need to indicate the serial number of a dead drive in order for it to be replaced. Once the disk is dead, using hardware.txt can be the only way to retrieve this info.

handlers/sys.in

@@ -594,7 +594,7 @@ if [ "$hardware" == "yes" ]; then
       echo -e "\n\n====================== summary ======================\n" >>  $hardwarefile
       debug "$HWINFO --short --cpu --network --disk --pci  >> $hardwarefile"
       $HWINFO --short --cpu --network --disk --pci  >> $hardwarefile
-      for flag in cpu network bios pci; do
+      for flag in cpu network disk bios pci; do
          echo -e "\n\n====================== $flag ======================\n" >>  $hardwarefile
          $HWINFO --$flag >> $hardwarefile
       done