Correct request formation as identified in #393

[eddelbuettel]

As identified by @mtkerbeR in #393, there was a Name{} invocation too many which bricked bds(). This restores it.

Many thanks to @mtkerbeR for catching this and the patient testing.

[mtkerbeR]

I think line 271 has to be adjusted as well, as it is still sufferign from the same problem - namely a Name{} within appendValue()

request.getElement(Name{"fields"}).appendValue(Name{field.c_str()});

[eddelbuettel]

And lines 314 and 316.

[mtkerbeR]

Just to confirm: After adjusting lines 314 and 316, function getPorfolio() works as expected as well.
I think there is no test case for this function as the portfolio IDs used as a paramter are client specific, i.e. cannot be tested by people not within the same organization.