Don't use sed -r; instead use old-style regexp
Rev d895158fe8af introduced some sed -r tests, but -r is only available on GNU
sed, while BSD sed uses -E. Better to use old-style regular expressions, that
way the tests work on all sed variants.
% create test repository
adding a
adding b
adding c
% churn separate directories
user1 1 ***************************************************************
% churn all
user3 3 ***************************************************************
user1 3 ***************************************************************
user2 2 ******************************************
% churn up to rev 2
user2 2 ***************************************************************
user1 1 *******************************
% churn with aliases
alias3 3 **************************************************************
alias1 3 **************************************************************
user2 2 *****************************************
% churn with column specifier
user3 3 ***********************
user1 3 ***********************
user2 2 ***************
% churn by hour
06 1 ****************
09 2 *********************************
12 4 ******************************************************************
13 1 ****************