Add a more verbose description on the IllegalStateException fix on WFLY-9821

Parent issue: https://issues.jboss.org/browse/WFLY-9821

We throw an IlegalStateException, when an attempt is made to call the CDI container before the container is actually started with the use of CDI.current().

Although the fix clearly states its not the correct way to set the state, we throw an Exception. The deployments succeed, but a non-expert CDI user might not expect an exception, and probably it would leave them confused on what is wrong, unless they understand what they have done in their own application code.

My thought and wish was, if we can add some log.WARN message in the condition describing why this happens, would be nice! It provides you with hints on what is NOT to be done in your application code.