Handle network disconnections smoothly

[arky]

While groundcontrol is branching a local project I disconnected the wireless connection just to see what happens. I thought it will fall back on ethernet wired connection but instead it gave a broken pipe error.

** (nm-applet:3974): DEBUG: going for offline with icon: notification-network-wireless-disconnected
Write failed: Broken pipe
ERROR:root:Connection closed: Unexpected end of message. Please check connectivity and permissions, and report a bug if problems persist.
Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/GroundControl/base.py", line 72, in run
    super(Thread, self).run(*args, **kwargs)
  File "/usr/lib/python2.6/threading.py", line 479, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib/python2.6/dist-packages/GroundControl/bazaar.py", line 314, in inital_thread
    self.do_action()
  File "/usr/lib/python2.6/dist-packages/GroundControl/bazaar.py", line 380, in do_action
    branched = self.branch.branch.bzrdir.sprout(dest_dir).open_branch()
  File "/usr/lib/python2.6/dist-packages/bzrlib/bzrdir.py", line 1183, in sprout
    result_repo.fetch(source_repository, revision_id=revision_id)
  File "/usr/lib/python2.6/dist-packages/bzrlib/repository.py", line 1695, in fetch
    find_ghosts=find_ghosts, fetch_spec=fetch_spec)
  File "<string>", line 4, in fetch_write_locked
  File "/usr/lib/python2.6/dist-packages/bzrlib/repository.py", line 3413, in fetch
    pb=pb, find_ghosts=find_ghosts)
  File "/usr/lib/python2.6/dist-packages/bzrlib/fetch.py", line 81, in __init__
    self.__fetch()
  File "/usr/lib/python2.6/dist-packages/bzrlib/fetch.py", line 107, in __fetch
    self._fetch_everything_for_search(search)
  File "/usr/lib/python2.6/dist-packages/bzrlib/fetch.py", line 135, in _fetch_everything_for_search
    stream, from_format, [])
  File "/usr/lib/python2.6/dist-packages/bzrlib/repository.py", line 4238, in insert_stream
    return self._locked_insert_stream(stream, src_format, is_resume)
  File "/usr/lib/python2.6/dist-packages/bzrlib/repository.py", line 4271, in _locked_insert_stream
    self.target_repo.texts.insert_record_stream(substream)
  File "/usr/lib/python2.6/dist-packages/bzrlib/groupcompress.py", line 1608, in insert_record_stream
    for _ in self._insert_record_stream(stream, random_id=False):
  File "/usr/lib/python2.6/dist-packages/bzrlib/groupcompress.py", line 1663, in _insert_record_stream
    for record in stream:
  File "/usr/lib/python2.6/dist-packages/bzrlib/versionedfile.py", line 1604, in read
    for bytes in self._bytes_iterator:
  File "/usr/lib/python2.6/dist-packages/bzrlib/smart/repository.py", line 570, in iter_substream_bytes
    for record in self.iter_pack_records:
  File "/usr/lib/python2.6/dist-packages/bzrlib/smart/repository.py", line 560, in iter_stream_decoder
    for bytes in self.byte_stream:
  File "/usr/lib/python2.6/dist-packages/bzrlib/smart/message.py", line 336, in read_streamed_body
    self._read_more()
  File "/usr/lib/python2.6/dist-packages/bzrlib/smart/message.py", line 286, in _read_more
    "Unexpected end of message. "
ConnectionReset: Connection closed: Unexpected end of message. Please check connectivity and permissions, and report a bug if problems persist.