refactor: migrate server-framework to depend on libkos

crates/server-framework/src/executor/mod.rs

@@ -28,7 +28,7 @@ pub fn block_on<F: Future>(future: F) -> F::Output {
             Poll::Ready(output) => return output,
             Poll::Pending => {
                 #[cfg(not(test))]
-                userspace::syscall::yield_now();
+                libkos::syscall::yield_now();
             }
         }
     }