Add ability to specify source credentials if required

PROD-31387

Change-Id: I6425a37a3f179e13c5e6cb4184855169a0df63cf
diff --git a/vnf_onboarding/vnf/avi_loadbalancer/mirrors.yml b/vnf_onboarding/vnf/avi_loadbalancer/mirrors.yml
index c74bda3..0b47570 100644
--- a/vnf_onboarding/vnf/avi_loadbalancer/mirrors.yml
+++ b/vnf_onboarding/vnf/avi_loadbalancer/mirrors.yml
@@ -7,4 +7,5 @@
       - name: avi-loadbalancer
         downstream: vnf-onboarding/avi-loadbalancer
         upstream: ${_param:gerrit_vnf_onboaring_avi_repo}
-        branches: master
\ No newline at end of file
+        branches: master
+        source_credentials: "${_param:vnf_onboaring_source_credentials}"
\ No newline at end of file