tests/test-empty-dir.t

bundle2: also save output when error happens during part processing

Until this changeset, we were only able to save output if an error happened
during the 'transaction.close()' phase. If the 'processbundle' call raised an
exception, the 'bundleoperation' object was never returned, so the reply bundle
was never accessible and no output could be salvaged. We introduce a quick (but
not very elegant) fix to gain access to any reply created during the processing.

This conclude this output related series. We should hopefully be able client-side to see the
whole server output, in a proper order.

The code is now complex enough that a refactoring of it would make sense on
default.

  $ hg init

  $ echo 123 > a
  $ hg add a
  $ hg commit -m "first" a

  $ mkdir sub
  $ echo 321 > sub/b
  $ hg add sub/b
  $ hg commit -m "second" sub/b

  $ cat sub/b
  321

  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ cat sub/b 2>/dev/null || echo "sub/b not present"
  sub/b not present

  $ test -d sub || echo "sub not present"
  sub not present