[Development] Online installer no longer lets users choose between Qt 5.3.0 and Qt 5.3.1

[Kalinowski Maurice]

> > It's certainly possible, but I'm not sure whether it's really worth
> > it, given that we still have offline installers.
> 
> Is it possible to use the offline installer to install 5.3.0 into the existing
> installation and not install a new Qt Creator?
> 
[> ] 
No. Installer does not check for potential relationships.
Still your regular installation can use the 5.3.0 install easily.

Maurice