This issue is a clone of: MULTISITE-19

Original description:
"
No matter whether you own standard or pro license you're allowed to install this enterprise module. However if you reconfigure it to provide only one site definition in order to meet your license agreement, your log files are still flooded by License issue: No valid license found for MultiSite!."

Solution form MULTISITE-19 as a comment, which I think is wrong!
"MultiSiteManager#isEELicensed now only logs a warning if a non-pro ee license has more then one site."

This solution just doesn't make sense:
When adding a demo, travel or stk, you will have more than one site definition.
And this should be ok, HAVING multiple Site Definitions does not mean that the system HAS TO USE them. Its a cheap solution restricting the amount of site definitions by bombarding the log file.
Why should I not have more then one, having the fallback extending one and using the extended one. So I can try out different site definitions by extending once site def A and then site def B. This is still ONLY using one at the time, which is fully ok. Or backing up one by just duplication it, before changing something -> and the log is flooded again...