hs-test: keep ab/wrk containers alive until teardown

- Fixes errors while obtaining container logs on test failure
  (NginxPerf tests), ab/wrk containers are now stopped on test teardown
  like other containers.

Type: test

Change-Id: Ic336fcd3ed6bf68dd345d378262cb28eb5efc789
Signed-off-by: Adrian Villin <avillin@cisco.com>
diff --git a/extras/hs-test/container.go b/extras/hs-test/container.go
index 44d84d5..080eb73 100644
--- a/extras/hs-test/container.go
+++ b/extras/hs-test/container.go
@@ -180,7 +180,7 @@
 
 	cmd := "docker run "
 	if c.runDetached {
-		cmd += " -d"
+		cmd += " -dt"
 	}
 
 	c.allocateCpus()