Fixing runtime wiring issue of virtual nets app

Change-Id: I046e35158381145de371564ae2912aa18451d619
diff --git a/apps/virtual/BUILD b/apps/virtual/BUILD
index 1f3cb57..0aeb389 100644
--- a/apps/virtual/BUILD
+++ b/apps/virtual/BUILD
@@ -8,6 +8,9 @@
     category = "Traffic Engineering",
     description = "Virtual Network Subsystem extension",
     included_bundles = BUNDLES,
+    required_apps = [
+        "org.onosproject.tunnel",
+    ],
     title = "Virtual Network Subsystem",
     url = "http://onosproject.org",
 )