Icon: use size_hint_min instead of image_size to know the wanted size
Icon: use size_hint_min instead of image_size to know the wanted size

This @fix fdo icons to load the correct image for the requested size.

Whitout this the small images (16x16) was never used, because once a big
(64x64 for example) image was loaded, that size was used as min.

See the Icon Standard test for a better explanation

rvandegrift/elementary,tasn/elementary,tasn/elementary,rvandegrift/elementary,rvandegrift/elementary,FlorentRevest/Elementary,tasn/elementary,FlorentRevest/Elementary,tasn/elementary,rvandegrift/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,tasn/elementary