localrepo: rename in-memory tag cache instance attributes (
issue548).
- self.tagscache to self._tags
- self._tagstypecache to self._tagtypes
- this is for consistency, readability, privacy, and to subtly hint
that "caching" is something else
#!/bin/sh
hg init a
cd a
hg -v log -v
hg -v log -v x
true