Explicitly tell aptly where its configuration file lives

Change-Id: I15942d9308c360557a065dac53542bbe97c765e5
diff --git a/cicd/pipelines/tasks/task_publish_unstable.jenkins b/cicd/pipelines/tasks/task_publish_unstable.jenkins
index a4f76f9..fdcba7a 100644
--- a/cicd/pipelines/tasks/task_publish_unstable.jenkins
+++ b/cicd/pipelines/tasks/task_publish_unstable.jenkins
@@ -41,8 +41,8 @@
                     sh """
                        mkdir -p /var/lib/aptly/publishes/unstable
                        aptly snapshot merge core-full-unstable-${stamp} ${debianMirrorSnapshotName} ${coreSnapshotName}
-                       aptly publish snapshot --distribution=unstable core-full-unstable-${stamp} filesystem:unstable:unstable
-                       aptly publish snapshot --distribution=unstable ${bspSnapshotName} filesystem:unstable:unstable
+                       aptly publish snapshot --config=/etc/aptly.conf --distribution=unstable core-full-unstable-${stamp} filesystem:unstable:unstable
+                       aptly publish snapshot --config=/etc/aptly.conf --distribution=unstable ${bspSnapshotName} filesystem:unstable:unstable
                        """
                 }
             }