Remove unused feature filter.

src/cargo/core/compiler/context/unit_dependencies.rs

@@ -162,12 +162,6 @@ fn compute_deps<'a, 'cfg, 'tmp>(
                 return false;
             }
 
-            // If the dependency is optional, then we're only activating it
-            // if the corresponding feature was activated
-            if dep.is_optional() && !bcx.resolve.features(id).contains(&*dep.name_in_toml()) {
-                return false;
-            }
-
             // If we've gotten past all that, then this dependency is
             // actually used!
             true