Downgrade Vala version requirements
Downgrade Vala version requirements

Downgrade required version to 0.3.4, that comes with Debian Stable.

Right now, we do not have any reason to need 0.7.5. If in future we need it,
then we will upgrade it.

MathieuDuponchelle/grilo,GNOME/grilo,kyoushuu/grilo,grilofw/grilo,jasuarez/grilo,grilofw/grilo,kyoushuu/grilo,GNOME/grilo,jasuarez/grilo,jasuarez/grilo,MathieuDuponchelle/grilo,kyoushuu/grilo,MathieuDuponchelle/grilo,grilofw/grilo,kyoushuu/grilo