[varnishcache/varnish-cache] 765b6d: Restart epoll_wait on EINTR error

[Martin Blix Grydeland]

  Branch: refs/heads/master
  Home:   https://github.com/varnishcache/varnish-cache
  Commit: 765b6d3b3bb6f96e2c5945abe998ba9016327116
      https://github.com/varnishcache/varnish-cache/commit/765b6d3b3bb6f96e2c5945abe998ba9016327116
  Author: Martin Blix Grydeland <martin at varnish-software.com>
  Date:   2015-12-04 (Fri, 04 Dec 2015)

  Changed paths:
    M bin/varnishd/waiter/cache_waiter_epoll.c

  Log Message:
  -----------
  Restart epoll_wait on EINTR error

This works around a Linux kernel bug where the epoll_wait will return
EINTR when the process is subjected to a ptrace or the OS wakes from
suspend.

Fixes: #1763