serve: respect settings from .hg/hgrc
create_server was looking only at the root ui object, ignoring any
settings from .hg/hgrc. To keep respecting command-line arguments,
commands.serve must also call repo.ui.setconfig.
%% Should show unknown
? unknown
removing b
%% Should show unknown and b removed
R b
? unknown
%% Should show a and unknown
a
unknown