NiFiClientUtil.getUrl Does Not Use Configured WEB_HTTP_PORT

I ran into this when attempting to use the node-manager.sh tool to get cluster status. The node was configured with a custom WEB_HTTP_PORT in nifi.properties, but it still attempted to use WEB_HTTP_HOST:8080 to contact the node. After some digging I found the problem here: https://github.com/apache/nifi/blob/master/nifi-toolkit/nifi-toolkit-admin/src/main/groovy/org/apache/nifi/toolkit/admin/client/NiFiClientUtil.groovy#L59

Basically getUrl tries to use the WEB_HTTPS_PORT if configured, but ends up defaulting to 8080 since to get into that else block, WEB_HTTPS_PORT was already empty.

This bug probably effects the NotificationTool in addition to the NodeManagerTool.