requirements from replacements do not come from the lock file

I think the core of the problem is that 725420e was a mistake. Before that PR we used `=` constraints to imply that it came from lock file so when we saw a `=` constraints being constructed for a replace it should use the new system for marking something as coming from lock file. But I don't think that is the semantics that an `=` constraint implies in this context.

Author: Eh2406

src/cargo/util/toml/mod.rs

@@ -1274,8 +1274,7 @@ impl TomlManifest {
                 replacement.unused_keys(),
                 &mut cx.warnings,
             );
-            dep.set_version_req(OptVersionReq::exact(&version))
-                .lock_version(&version);
+            dep.set_version_req(OptVersionReq::exact(&version));
             replace.push((spec, dep));
         }
         Ok(replace)