Allow the user to specify the fallback encoding for the changelog
Example: use EUC-JP instead of ISO-8859-1:
[ui]
fallbackencoding = EUC-JP
foo renamed from bar:26d3ca0dfd18e44d796b564e38dd173c9668d3a9
rev offset length base linkrev nodeid p1 p2
0 0 6 0 0 26d3ca0dfd18 000000000000 000000000000
1 6 7 1 1 d267bddd54f7 26d3ca0dfd18 000000000000