[releng] make sure the parent directories are in place before the mv

Change-Id: I446681635b13298b2e9c41112323d07126b846e5
diff --git a/releng/org.eclipse.epp.config/tools/promote-a-build.sh b/releng/org.eclipse.epp.config/tools/promote-a-build.sh
index 0f92892..d1a6a16 100755
--- a/releng/org.eclipse.epp.config/tools/promote-a-build.sh
+++ b/releng/org.eclipse.epp.config/tools/promote-a-build.sh
@@ -28,6 +28,7 @@
 # Move the repo and downloads into their location
 
 $ECHO $SSH mkdir -p ${REPO}
+$ECHO $SSH mkdir -p ${DOWNLOADS}
 $ECHO $SSH mv ${EPP_DOWNLOADS}/staging/repository ${REPO}/${RELEASE_DIR}
 if [ "$RELEASE_MILESTONE" != "R" ]; then
     $ECHO $SSH mv ${EPP_DOWNLOADS}/staging ${DOWNLOADS}/${RELEASE_MILESTONE}