just-mr: rework progress reporting and statistics

To avoid unnecessary work, just-mr uses on-disk caches, including
for the mapping of a distdir to the corresponding git tree. This,
however, implies that the number of repositories that are actually
considered varies: in order to fetch a distdir repository, all
involved archives have to be fetched, but if we have a cache hit
none of them is even looked at.

So, in order to have a consistent reporting only count top-level
targets (i.e., the reachable repositories) in the statistics,
not the archives implicitly contained in a distdir, nor low-level
sub tasks. The actual fetch acitvity is shown separately by the
task tracker.

0 files changed, 0 insertions, 0 deletions