MULE-6560: Incorrect value in recommended JDK version checking
MULE-6559: Wrong messages on JDK version validation
Supported jdk version is now >= 1.6. If jdk < 1.6 refuse to start. If jdk is from unsupported vendor, log info message. Messages are now clearer.
(cherry picked from commit f61021ff0c1c18e02834f341f4f2cb32733ef246)