evas: Fix image save with GL engine and orientation

evas: Fix image save with GL engine and orientation

This fixes evas_object_image_save after changing the orientation
of an image in the GL engine. In SW engine the pixel data is rotated
in memory, so things worked fine from the beginning. In GL we may
have to go through loops and hoops in order to rotate and fetch the
data from the GL texture.

This should fix ce45d44.