Fix inverted order of unloading streaming ANI files.

When streaming an ANI file, first anim_load() is called, then init_anim_instance(). The latter increments the animation's instance_count. If anim_free() is called on an animation that still has instances, it refuses to free the animation. generic_anim_unload() first called anim_free(), then free_anim_instance().

The fact that ANI files would ever unload at all seems to be because some code would unload twice. I can only assume that, combined with the fact that the bug only applies to ANI files, explains how this bug went undetected since November of 2009 (commit b434178 seems to be when it was added, from a quick glance at git blame).

Author: MageKing17

code/graphics/generic.cpp

@@ -323,8 +323,8 @@ void generic_anim_unload(generic_anim *ga)
 	if(ga->num_frames > 0) {
 		if(ga->streaming) {
 			if(ga->type == BM_TYPE_ANI) {
-				anim_free(ga->ani.animation);
 				free_anim_instance(ga->ani.instance);
+				anim_free(ga->ani.animation);
 			}
 			if(ga->type == BM_TYPE_EFF) {
 				if(ga->eff.next_frame >= 0)