fix(dracut.sh): inform user about auto-selected compression method

If the compression method is unset, or had to be reset because of
missing dependencies, inform the user what's being used. Also,
replace the printf in the "cat" case with a dwarn.

dracut.sh

@@ -2358,7 +2358,9 @@ if ! [[ $compress ]]; then
         break
     done
     if [[ $compress == cat ]]; then
-        printf "%s\n" "dracut: no compression tool available. Initramfs image is going to be big." >&2
+        dwarn "dracut: no compression tool available. Initramfs image is going to be big."
+    else
+        dinfo "dracut: using auto-determined compression method '$compress'"
     fi
 fi