Prevent type exception on concatenation if diffstat returns None.
This will most often occur if diffstat is not installed in the
target platform, though may also happen in other cases where
diffstat fails to execute.
Signed-off-by: Sean Dague <sean@dague.net>
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)