Spurious WARN at startup on Oracle JDK

[rocketraman]

Minor issue with cfg4k 0.9.0: always get this WARN level message from PropertyConfigLoader at startup, using Oracle JDK 1.8:

Key (java.vendor.url.bug=Oracle Corporation) has overridden another value used as root

[jdiazcano]

This is going to be disabled the next version but for now it is ok, nothing is wrong.

There's a java.vendor and another key that is actually overridden due to property design.

Leaving it open for visibility