addbackup: use the vfs for the backup destination too The backup file location was always computed using the opener, bypassing the 'location' setting. (And making the feature broken.)

transaction: set backupentries version to proper value Now that all mechanisms are in place, we can advertise it with a proper new version.

transaction: support cache file in backupentries We do not want to abort if anything wrong happen while handling a cache file. Cache file have way to be invalidated and if old/bad version stay no misbehavior will happen. Proper value will eventually be computed and the wrong will be righten. This changeset use the transaction reporter (usually writing on stderr) to write details about failed cache handling. This will only apply to write operation using a transaction. The usual update during read only operation will stay a debug message. I was on the way to bring these message back to debug level when I realised it could be a feature. People with write access to the repository are likely to have the power to fix error related to cache (and it is valuable to fix them). So let the things as is for now.

transaction: use the location value when doing backup We finally use the 'location' value coupled with the 'vfsmap' to restore backup for the right file.

transaction: pass a vfs map to the transaction The goal is to allow access to file outside ofthe store directory from the transaction. The obvious target are the `bookmarks` file. But we can envision usage for cache too. We keep passing a main opener explicitly because a lot of code rely on this default opener. The main opener (operating on store) is using an empty key ''.

transaction: change the on disk format for backupentries We need to store new data to improve the current transaction logic: - location: We want to generate and backup file outside of the 'store' (eg: bookmarks, or various cache files). This requires knowing and preserving where each file is located. The value of this new field is a string. It will be used as a key for a vfs mapping. - cache: We would like to handle cache file in the transaction code. This Will help to have cache consistent with the repository state and avoid performance issue on big repository like Mozilla. However, failure to handle cache file should not result in a transaction failure. We add a new field that carry this information. The value is boolean, A True value mean any error while handling this file can be ignored. Those two mechanisms are not implemented yet, but they are now persisted in the on disk file. Support for new mechanisms is coming in later changeset. We update the file format now and will introduce the new features in later changeset. The format version is set to 0 until we actually support the new feature. This will prevent misunderstanding between incomplete and final client. Support for reading both version 1 and (future) version 2 could be achieved (using default value when reading version 1) but has not been seen as necessary for now.

silenttestrunner: add environment variable to make tests noisy again As I've been working on complicated extension code it's been handy to be able to get standard unittest verbose output so I can find crashers more efficiently.