AuthPolicy: remove extraneous std::move call

This change removes an unnecessary call to std::move in
AuthPolicyClient::ConnectToSignal.

Bug: none
Change-Id: Id7fcb10e6b188d0a3058815c3078405f9634801a
Reviewed-on: https://chromium-review.googlesource.com/1028229Reviewed-by: Lutz Justen <ljusten@chromium.org>
Reviewed-by: Roman Sorokin <rsorokin@chromium.org>
Commit-Queue: Roman Sorokin <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553958}

chromeos/dbus/auth_policy_client.cc

@@ -154,8 +154,8 @@ class AuthPolicyClientImpl : public AuthPolicyClient {
       const std::string& signal_name,
       dbus::ObjectProxy::SignalCallback signal_callback,
       dbus::ObjectProxy::OnConnectedCallback on_connected_callback) override {
-    proxy_->ConnectToSignal(authpolicy::kAuthPolicyInterface,
-                            std::move(signal_name), std::move(signal_callback),
+    proxy_->ConnectToSignal(authpolicy::kAuthPolicyInterface, signal_name,
+                            std::move(signal_callback),
                             std::move(on_connected_callback));
   }