Revert "Add UID permission check to update_engine"

This reverts commit 596969b84d101cb494ec5faeb6cdd277e51c165c.

Reason for revert: Pixel doesn't go through system_server for update_engine APIs, therefore UID is not system

Change-Id: I7723e4c8b35f5f252eadb36b2a871a0b24950805
diff --git a/common/daemon_state_interface.h b/common/daemon_state_interface.h
index d6cf9da..831e38b 100644
--- a/common/daemon_state_interface.h
+++ b/common/daemon_state_interface.h
@@ -41,7 +41,8 @@
 
  protected:
   DaemonStateInterface() = default;
-  DaemonStateInterface(const DaemonStateInterface&) = delete;
+
+  DISALLOW_COPY_AND_ASSIGN(DaemonStateInterface);
 };
 
 }  // namespace chromeos_update_engine