udev: update hotplug block scripts for QubesDB

Some initial work was done, but apparently not complete and buggy.

udev/udev-block-add-change

@@ -63,8 +63,8 @@ fi
 # The last one is meant to trigger watches
 qubesdb-write \
     "$QDB_KEY/desc" "$DESC" \
-    "$XS_KEY/size" "$SIZE" \
-    "$XS_KEY/mode" "$MODE" \
+    "$QDB_KEY/size" "$SIZE" \
+    "$QDB_KEY/mode" "$MODE" \
     /qubes-block-devices ''
 echo QUBES_EXPOSED=1
 

udev/udev-block-remove

@@ -2,7 +2,9 @@
 
 NAME=${DEVNAME#/dev/}
 QDB_KEY="/qubes-block-devices/$NAME"
-qubesdb-rm "$XS_KEY"
+# Trailing slash is intentional - it will remove whole directory, instead of
+# single base entry
+qubesdb-rm "$QDB_KEY/"
 qubesdb-write /qubes-block-devices ''
 
 # If device was connected to some VM - detach it