tests/test-status-inprocess.py.out

config: use the new '_unset' value for 'configdate'

This should let 'configdate' delegate all special processing of the default
config value to the main 'config' method.

The default value for date (None) is still enforced in this method if no other
default were passed.

% creating repo
% add and commit
C test.py
% change
M test.py