Setup Step 6. admin creation possible with incorrect db configuration

Under some conditions users can provide incorrect db connection details and still get to Step 6 of the setup - admin creation - at which point they will see something like this:

org.springframework.transaction.CannotCreateTransactionException: Could not create Hibernate transaction; nested exception is net.sf.hibernate.JDBCException: Cannot open connection

Stack Trace: [hide]

org.springframework.transaction.CannotCreateTransactionException: Could not create Hibernate transaction; nested exception is net.sf.hibernate.JDBCException: Cannot open connection
net.sf.hibernate.JDBCException: Cannot open connection

Fix - make it impossible to get past db setup unless the db connection is valid.