update: wlock the repo for the whole 'hg update' command The update command is touching the repository and should lock it for the length of its operations. Equally importantly, it should lock the repository when it is writing bookmarks. It wasn't doing so until now, leaving doors open for all kinds of drunk beaver parties. This results in some minor tests changes, and the fixing of a couple of bugs from race conditions. Code does not receive any changes beside extra indentation.