[4.1] a38f5ee In probes treat a poll timeout as a recv error

[Lasse Karstensen]

commit a38f5eecddb51d987af3922b5844e6192d04fa68
Author: Federico G. Schwindt <fgsch at lodoss.net>
Date:   Fri Mar 11 23:14:07 2016 +0000

    In probes treat a poll timeout as a recv error

diff --git a/bin/varnishd/cache/cache_backend_probe.c b/bin/varnishd/cache/cache_backend_probe.c
index e0590d8..c688cd0 100644
--- a/bin/varnishd/cache/cache_backend_probe.c
+++ b/bin/varnishd/cache/cache_backend_probe.c
@@ -271,6 +271,8 @@ vbp_poke(struct vbp_target *vt)
 		if (tmo > 0)
 			i = poll(pfd, 1, tmo);
 		if (i == 0 || tmo <= 0) {
+			if (i == 0)
+				vt->err_recv |= 1;
 			VTCP_close(&s);
 			return;
 		}