dracut.sh: strip NUL bytes in stream before push in string

seems like bash-4.4 does not like NUL bytes in variables

dracut.sh

@@ -1622,7 +1622,7 @@ if [[ $do_strip = yes ]] && ! [[ $DRACUT_FIPS_MODE ]]; then
     # strip kernel modules, but do not touch signed modules
     find "$initdir" -type f -path '*/lib/modules/*.ko' -print0 \
         | while read -r -d $'\0' f || [ -n "$f" ]; do
-        SIG=$(tail -c 28 "$f")
+        SIG=$(tail -c 28 "$f" | tr -d '\000')
         [[ $SIG == '~Module signature appended~' ]] || { printf "%s\000" "$f"; }
     done | xargs -r -0 strip -g