commit: use the term SCM instead of RCS
for consistency.
see also
fc4a3931e608
backout of
613b8bd2284e
Matt and a majority of crew did not like this approach.
check-code: do not complain about 'ls x | foo -v'
Such a line was introduced in test-subrepo-git.t in
5dda6c708138,
which made check-code confused.