style: Normalize variable expansions in libs.deprecated/*

These files stay deprecated and out of the sourcing path for now, but
apply the same ${var} notation cleanup as the rest of the repo where
it's a pure notation fix. basedir.bash is left untouched: its bug is
a broken escape, not a notation issue, and it mirrors the one already
removed from _helpers.bash.

libs.deprecated/ldif.bash

@@ -12,5 +12,5 @@ function ldifparse ()
 	if (length) print
 		next
 	}
-	{print}' "$FILE"
+	{print}' "${FILE}"
 }