Handle case where request_exit_status is called before the output is received.

Move output callback code from request_exit_status to eofReceived to ensure
that the data has all been received before sending the results back to the
callback.
Handle case where request_exit_status is called before the output is received.

Move output callback code from request_exit_status to eofReceived to ensure
that the data has all been received before sending the results back to the
callback.
Merge pull request #1 from zenoss/feature/channel_eof_fix

Feature/channel eof fix