Blender Git Loki

Fix T79111: Cycles: Image Sequence not rendering

Caused by c7aa0f9d743ee9cafe91b4a51d9f1ecc5e437d71.

Since above commit, BKE_image_user_frame_calc requires an image (not
just the iuser) to get the framenumber.

Cycles used to call this with NULL image (in `image_user_file_path` and
`image_user_frame_number`), now pass the image as well.

Maniphest Tasks: T79111

Differential Revision: https://developer.blender.org/D8439