jenkins: fix syntax error
@@ -188,7 +188,7 @@ def dockerImages() {
def retainNewestImages(image, n, withTag='', excludeTag='none') {
sh """docker images ${image} --format \"{{.Repository}} {{.Tag}}\" \
| grep -v \"${excludeTag}\" \
-| grep \"${withTag}\"
+| grep \"${withTag}\" \
| sort -k 2,2 \
| head -n -${n} \
| awk \'BEGIN{OFS=\":\"} {print \$1,\$2}' \
