[SailfishDevel] some inaccuracy on sailfishos wiki

[FIlip Kłębczyk]

https://sailfishos.org/wiki/Porting/Harmattan

In section 'Application Porting Tutorials'

"Some of these tutorials are still targeted towards the Alpha SDK (which 
had Qt 4 and X11), so be aware that additional porting steps might be 
required starting from the Beta SDK (which has Qt 5 and Wayland)"

Both SDKs are called Alpha so the text on wiki should be updated.

Regards,
Filip