Add missing US to ticker in one Equity example

[eddelbuettel]

As noted in #366 / #367 discussion. Do we have any other examples showing a (US) stock with the US ticker?

[johnlaing]

There's another one just a few lines below in the same file.

Also potentially here:

Rblpapi/src/beqs.cpp

Line 142 in a576b9f

std::string tickerValue = datapoint.getValueAsString() + std::string(" Equity");

Though I'm not quite sure what it's doing, so perhaps best to leave alone.

[eddelbuettel]

Line 142 is tricky. Maybe ticker is 'GOOG US'? It is also a conditional use, and the example in beqs.R uses non-ticker values :-/ Probably best to be left alone.

I adjusted the commit to README.md. Thanks for catching that. Not enough early morning coffee.