hs-test: refactor netconfig

This joins separate representations of veth and tap interfaces
into a single struct. It removes the need for type interface
and embedding which simplifies the code.

Type: test
Signed-off-by: Maros Ondrejicka <mondreji@cisco.com>
Change-Id: I1b2c368bfe90a5bdfaaa9a5129c27d7d96f8fe3b
diff --git a/extras/hs-test/http_test.go b/extras/hs-test/http_test.go
index 93705b2..96985be 100644
--- a/extras/hs-test/http_test.go
+++ b/extras/hs-test/http_test.go
@@ -51,7 +51,7 @@
 	err := vpp.waitForApp("-app", 5)
 	s.assertNil(err)
 
-	serverAddress := s.netInterfaces[tapNameVpp].IP4AddressString()
+	serverAddress := s.netInterfaces[tapInterfaceName].Peer().IP4AddressString()
 
 	defer func() { os.Remove(query) }()
 	go startWget(finished, serverAddress, "80", query, "")
@@ -64,7 +64,7 @@
 	var args []string
 	var exeName string
 
-	serverAddress := s.netInterfaces[tapNameVpp].IP4AddressString()
+	serverAddress := s.netInterfaces[tapInterfaceName].Peer().IP4AddressString()
 
 	if ab_or_wrk == "ab" {
 		args = []string{"-n", fmt.Sprintf("%d", nRequests), "-c",