evas_gl_generic: fix wrong gl context set
evas_object_image_native_surface_set(im, xx)-> MAIN CONTEXT
evas_gl_make_current -> CONTEXT A
evas_object_image_size_set(im, x,x) ->WRONG CONTEXT A
evas_object_image_size_set of image have native_surface finally calls
eng_image_size_set function of gl_generic.
eng_image_size_set cannot get the proper context related with
It ruined gl context and texture of main context has gone wrong.
Reviewed-by: Cedric BAIL <firstname.lastname@example.org>
Differential Revision: https://phab.enlightenment.org/D8338