message: Fix valgrind errors about passing uninitialized values to epoll
diff: @@ -185,8 +185,7 @@ ExternalCommitHelper::DaemonThread::DaemonThread()
  m_shutdown_read_fd = pipe_fd[0];
  m_shutdown_write_fd = pipe_fd[1];
  - struct epoll_event event;
  -
  + epoll_event event{};
  event.events = EPOLLIN;
  event.data.fd = m_shutdown_read_fd;
  ret = epoll_ctl(m_epoll_fd, EPOLL_CTL_ADD, m_shutdown_read_fd, &event);
  @@ -229,10 +228,10 @@ void ExternalCommitHelper::DaemonThread::add_commit_helper(ExternalCommitHelper*
  REALM_ASSERT(std::this_thread::get_id() != m_thread_id);
  std::lock_guard<std::mutex> lock(m_mutex);
  - struct epoll_event event;
  m_helpers.push_back(helper);
  + epoll_event event{};
  event.events = EPOLLIN | EPOLLET;
  event.data.fd = helper->m_notify_fd;
  int ret = epoll_ctl(m_epoll_fd, EPOLL_CTL_ADD, helper->m_notify_fd, &event);
  @@ -251,10 +250,9 @@ void ExternalCommitHelper::DaemonThread::remove_commit_helper(ExternalCommitHelp
  m_helpers.erase(std::remove(m_helpers.begin(), m_helpers.end(), helper), m_helpers.end());
  - struct epoll_event event;
  -
  // In kernel versions before 2.6.9, the EPOLL_CTL_DEL operation required a non-NULL pointer in event, even
  // though this argument is ignored. See man page of epoll_ctl.
  + epoll_event event{};
  epoll_ctl(m_epoll_fd, EPOLL_CTL_DEL, helper->m_notify_fd, &event);
  }
  @@ -265,7 +263,7 @@ void ExternalCommitHelper::DaemonThread::listen()
  int ret;
  while (true) {
  - struct epoll_event ev;
  + epoll_event ev{};
  ret = epoll_wait(m_epoll_fd, &ev, 1, -1);
  if (ret == -1 && errno == EINTR) {
  