Add ability to specify source credentials if required

PROD-31387

Change-Id: I6425a37a3f179e13c5e6cb4184855169a0df63cf
(cherry picked from commit dbae4e5621bf4ab3a771247f9789a0a6d4697545)
diff --git a/vnf_onboarding/common/mirrors.yml b/vnf_onboarding/common/mirrors.yml
index 83d11c0..c830d85 100644
--- a/vnf_onboarding/common/mirrors.yml
+++ b/vnf_onboarding/common/mirrors.yml
@@ -9,7 +9,9 @@
         downstream: vnf-onboarding/pipelines
         upstream: ${_param:gerrit_vnf_onboaring_pipelines_repo}
         branches: master
+        source_credentials: "${_param:vnf_onboaring_source_credentials}"
       - name: nfv-platform
         downstream: vnf-onboarding/nfv-platform
         upstream: ${_param:gerrit_vnf_onboaring_nfv_platform_repo}
-        branches: master
\ No newline at end of file
+        branches: master
+        source_credentials: "${_param:vnf_onboaring_source_credentials}"
\ No newline at end of file