pkg_manifest_validate: fix path joining and swap test around

kiss

@@ -699,7 +699,7 @@ pkg_manifest_validate() {
     log "$1" "Checking if manifest valid"
 
     while read -r line; do
-        [ -h "./$line" ] || [ -e "./$line" ] || {
+        [ -e "$tar_dir/$1$line" ] || [ -h "$tar_dir/$1$line" ] || {
             printf '%s\n' "$line"
             set -- "$@" "$line"
         }