Report stacktraces for remote_exec()

[joaoe]

Fix #101

[nicoddemus]

Besides my comment, this looks good to me. 👍

[nicoddemus]

Thanks again @joaoe and sorry for the delay on this! 👍

[nicoddemus]

1.7.0 released. 👍

[joaoe]

Excellent. Thank you :)

[alfredodeza]

this line right here just broke ceph-deploy when using remote modules. At this point in the code file_name exists along with source, so this line sets it to None which causes the channel to not send anything. The traceback is basically a generic EOFError which doesn't show much, I had to step through:

> /tmp/bad/local/lib/python2.7/site-packages/execnet/gateway.py(121)remote_exec()
    120             else:
--> 121                 source = None
    122         elif isinstance(source, types.FunctionType):

ipdb> file_name
'/home/alfredo/python/ceph-deploy/ceph_deploy/hosts/remotes.py'
ipdb> source
<module 'ceph_deploy.hosts.remotes' from '/home/alfredo/python/ceph-deploy/ceph_deploy/hosts/remotes.pyc'>
ipdb> n
> /tmp/bad/local/lib/python2.7/site-packages/execnet/gateway.py(129)remote_exec()
    128 
--> 129         if not call_name and kwargs:
    130             raise TypeError("can't pass kwargs to non-function remote_exec")

ipdb> source
ipdb> c

I will follow up with an issue, but IMHO there was no need for any optimization here whatsoever, which puts at risk code that depends on the robustness of the (current) implementation

[nicoddemus]

Thanks @alfredodeza