discovery: cleanup of variable names and comments

localrepo: give a sigh of relief when getting lock after waiting for it A message like this was sometimes shown when pushing: remote: waiting for lock on repository foo held by 'mercurial:20858' That could scare users, making them wonder whether the push actually succeeded. To mitigate that fear, issue an additional "warning" such as: got lock after 2 seconds The return value from lock.lock.lock() was unused - instead we return the delay. This also adds the first test coverage for waiting for locks.

convert: add tagmap option Tests have been updated.

convert: add tagmap logic Previously, there was no way to rewrite tags on the fly while converting. Now, we add similar logic to branchmap to provide a way to map old tags to new tags. Currently, this is not enabled since there is not yet a command-line option.