t / t4013 / diff.diff-tree_--cc_--stat_masteron commit diff: make sure --output=/bad/path is caught (8324b97)
   1$ git diff-tree --cc --stat master
   259d314ad6f356dd08601a4cd5e530381da3e3c64
   3 dir/sub |    2 ++
   4 file0   |    3 +++
   5 2 files changed, 5 insertions(+), 0 deletions(-)
   6$