filesystems: use udisks instead of sysfs to detect removable (not system-internal) devices

postplug.d/10filesystems

@@ -173,8 +173,7 @@ blkid | while read line; do
    [ "$label" ] || label="disk"
    if [ -e $dev ]; then
       # skip removable partitions
-      [ "`cat /sys/block/${dev:5:3}/removable 2>/dev/null`" = "1" \
-        -a ! -e /sys/block/${dev:5:3}/device/unload_heads ] && {
+      udisks --show-info $dev | grep "system internal:[[:space:]]*0$" || {
          [ "$DEBUG" ] && logmsg "$me" $"skipped device $dev ($uuid): removable"
 	 continue;
       }