sesman: reflect review suggestions on cleanup_sockets
sesman: reflect review suggestions on cleanup_sockets

* Use LOG_LEVEL_WARNING for the deletion failure
* Log the error condition when the deletion failed

PKRoma/xrdp,metalefty/xrdp,metalefty/xrdp,neutrinolabs/xrdp,PKRoma/xrdp,PKRoma/xrdp,metalefty/xrdp,neutrinolabs/xrdp,neutrinolabs/xrdp