Missing Java Option solr.log.dir. Logging may be missing or incomplete

I noticed this error in trunk demo error.log

2017-05-16 03:05:38,898 |0.0.0.0-startStop-1 |StartupLoggingUtils |E| Missing Java Option solr.log.dir. Logging may be missing or incomplete.

It's thrown by https://github.com/apache/lucene-solr/blob/master/solr/core/src/java/org/apache/solr/servlet/StartupLoggingUtils.java
I can't see nothing at https://localhost:8443/solr/#/~logging

On dev ML Jinghai suggested to add

def jvmArguments = ['-Xms128M', '-Xmx1024M',
	                '-Dsolr.log.dir=runtime/logs',
					'-Dsolr.log.level=INFO']

to main gradle. Taher mentionned that "The master build.gradle file should not point to any plugins"

I put the same in both lucene and solr components build. gradle (Solrs relies on Lucene but our usage is specific) and saw no drawbacks.

I must say I was not able to reproduce the "error" locally. But I anyway I propose to commit in the 2 plugins to reassur people who could else wonder.