Remove old_sqlite feature

And associated bindgen_3.6.8.rs

src/util/mod.rs

@@ -5,7 +5,5 @@ pub(crate) use param_cache::ParamIndexCache;
 pub(crate) use small_cstr::SmallCString;
 
 // Doesn't use any modern features or vtab stuff, but is only used by them.
-#[cfg(any(not(feature = "old_sqlite"), feature = "vtab"))]
 mod sqlite_string;
-#[cfg(any(not(feature = "old_sqlite"), feature = "vtab"))]
 pub(crate) use sqlite_string::SqliteMallocString;

src/util/sqlite_string.rs

@@ -1,10 +1,7 @@
 // This is used when either vtab or modern-sqlite is on. Different methods are
 // used in each feature. Avoid having to track this for each function. We will
 // still warn for anything that's not used by either, though.
-#![cfg_attr(
-    not(all(feature = "vtab", not(feature = "old_sqlite"))),
-    allow(dead_code)
-)]
+#![cfg_attr(not(feature = "vtab"), allow(dead_code))]
 use crate::ffi;
 use std::marker::PhantomData;
 use std::os::raw::{c_char, c_int};