fix when changelog not available

Change-Id: I0c119052a662ff67371c6c430fbd9a7753852cc7
Signed-off-by: Mike Marchetti <mmarchetti@sandvine.com>

jenkins/ci-pipelines/ci_stage_3.groovy

@@ -133,7 +133,7 @@ node("${params.NODE}") {
                 // merge the change logs
                 sh """
                    rm -f changelog/osm-changelog.html
-                   [ -d changelog ] && for mdgchange in \$(ls changelog); do cat changelog/\$mdgchange >> changelog/osm-changelog.html; done
+                   [ ! -d changelog ] || for mdgchange in \$(ls changelog); do cat changelog/\$mdgchange >> changelog/osm-changelog.html; done
                    """
             }
             // start an apache server to serve up the images