tests/test-issue433

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
# http://mercurial.selenic.com/bts/issue433

hg init a
cd a
echo a > a
hg commit -Ama

hg parents -r 0 doesnotexist
true