Fix "RefCountObjectReleaser" move-assignment operator. Current operator properly assigns only to an empty object. No actual problem in the current code. May be problems in a new, especially in a debug code like this: releaseImage = {}; The above line will not release resources as expected, and may waste a lot of time during debugging process. Bug: None Change-Id: I0fe064b68ade9211fdef5790ed3c41b0101cfa93 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4262069 Commit-Queue: Igor Nazarov <i.nazarov@samsung.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>