Fix skipGroup user propagation for Git/HTTP pushes When commits are pushed using Git/HTTP, the receive commit is executed in a separate asynchronous thread that does not inherit the same thread-local context. Get the user from the receiveEvent so that skip by group can work reliably on both Git/SSH and Git/HTTP pushes. Change-Id: I42c7b0062fcb2d188c2fd67fbaa0f41705d1aced