WebPPictureDistortion(): free() -> WebPSafeFree()
WebPPictureDistortion(): free() -> WebPSafeFree()

missed one!

Change-Id: I643170451b3ac07c748b70a9abfe8af17a716b24
(cherry picked from commit 32dead4ee384afa8dc4da9a8a9d49ab944318c35)

PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,webmproject/libwebp,webmproject/libwebp,PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,PKRoma/libwebp