[Typo3] Install tool and database name check

[Mike Fabricius]

> Trying to install a 3.8 from scratch I came across the following error:
> 
> Host 'database-6.db.widexs.nl' was not alphanumeric, a-zA-Z0-9_-:., or 
> longer than 50 chars (...not saved)
> 
> which seems a bit harsh: this is a legal name for a server isn't it? 
> Shouldn't the script let this pass ( the '-' in the name)?

I had exactly the same problem. My hostname is mysql4db-1.gradwell.net.
I ended up manually putting the details into localconf.php and manuall 
importing database.sql into the database. Then it worked.

Mike