oeqa/core/utils/concurrencytest.py: Handle exceptions and details
Handle the streaming of exception content with details data. The
testtools package allows both 'err' and 'details' kwargs but can only
pass one of them to the parent.
To handle the passing of exception traceback and details data at the
same time, encode the traceback into the details object and remove the
'err' arg from the add* result call. This encodes the traceback similar
to how 'err' is handled without any details object. Decoding is already
done by testtools when the traceback is encoded in the details object.
Signed-off-by: Nathan Rossi <nathan@nathanrossi.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
