flimflam: fix use-after-free of hidden network

flimflam: fix use-after-free of hidden network

When a hidden network fails to connect the cleanup work reclaims the
network block prematurely causing multiple references after memory is
free'd.  Fix this by holding a reference over the code that might free
the state and also do not do a deferred update of the device state if
the network is unregistered as this is guaranteed to fail and unneeded
because device state cleanup is already handled at a higher level.

This case can easily be reproduced by connecting to non-existent network;
on timeout badness happens as described above.

BUG=chromium-os:8871, chromium-os:8587
(and probably others)
TEST=manual:see above (done under gdb and with wifi+network+service msgs)

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=51c10a9

[Paul Stewart, 2010-11-30 23:27:10]

LGTM.  BTW, your BUG= lines create links to the chromium bug database, not
chromium-os.  Please use "BUG=chromium-os:8871,chromium-os:8587" instead.