Don't require junit results on igmpproxy and mcast (including current) jobs

Change-Id: Icf3c11b98daed70cb24e79d597a1f164bed4ef6f
diff --git a/jjb/verify/mcast.yaml b/jjb/verify/mcast.yaml
index 329e415..a79f955 100644
--- a/jjb/verify/mcast.yaml
+++ b/jjb/verify/mcast.yaml
@@ -11,6 +11,7 @@
 
       - 'mcast-jobs':
           branch-regexp: '^(master)$'
+          junit-allow-empty-results: true
 
       - 'mcast-jobs-legacy':
           branch-regexp: '^(mcast-1.4)$'