qt5-5.6.1: use tar.gz (instead of tar.xz) for SOURCE_URI. (#817)
qt5-5.6.1: use tar.gz (instead of tar.xz) for SOURCE_URI. (#817)

Also remove trailing whitespaces.
haikuports/haikuports,nielx/haikuports,haikuports/haikuports,Begasus/haikuports,Begasus/haikuports,haikuports/haikuports,moochris/haikuports,koletzky/haikuports,koletzky/haikuports,miqlas/haikuports,nielx/haikuports,Begasus/haikuports,Begasus/haikuports,moochris/haikuports,Begasus/haikuports,haikuports/haikuports,haikuports/haikuports,miqlas/haikuports,koletzky/haikuports,nielx/haikuports,miqlas/haikuports,moochris/haikuports