Stabilize this test on CentOs

bin/varnishtest/tests/c00105.vtc

 varnishtest "Failed post-streaming revalidation"
 
-barrier b1 cond 2
+barrier b1 cond 3
 barrier b2 sock 2
-barrier b3 sock 2
 
 server s1 {
 	rxreq
@@ -20,7 +19,6 @@ server s2 {
 varnish v1 -cliok "param.set vsl_mask +ExpKill"
 
 varnish v1 -vcl+backend {
-	import directors;
 	import vtc;
 
 	sub vcl_recv {
@@ -32,7 +30,6 @@ varnish v1 -vcl+backend {
 	sub vcl_backend_response {
 		if (beresp.was_304) {
 			vtc.barrier_sync("${b2_sock}");
-			vtc.barrier_sync("${b3_sock}");
 		}
 		set beresp.ttl = 1ms;
 	}
@@ -46,20 +43,21 @@ client c1 {
 	txreq -hdr "backend: s1"
 	rxresphdrs
 	expect resp.status == 200
+	barrier b1 sync
 	expect_close
 } -start
 
-barrier b1 sync
-
 logexpect l1 -wait
 
+varnish v1 -vsl_catchup
+
+barrier b1 sync
+
 client c2 {
 	txreq -hdr "backend: s2"
 	rxresphdrs
 	expect resp.status == 200
 	expect_close
-} -start
+} -run
 
 client c1 -wait
-barrier b3 sync
-client c2 -wait