Dup bucket name creation can be caught much earlier and provide better user experience

Dup bucket name creation can be caught much earlier and provide better user experience.
As seen from we already know there is no way travel-sample bucket would be created as we already have one with same name, but we don't do it until the last tab.

Not exactly a bug, but with max of 30 buckets allowed and also talk of increasing it to 50 or more this would be a useful feature.