same exportAttributes from two DataConnectors

[Rod Widdowson]

> I had thought things got merged, 

The only thing that get merged are explicit attribute definitions.  This warning is the principal of least surprise.  It is
important now, but it was vital when we still thought that exportAll (not thoroughly deprecated) was a good idea.

>  Like Scot says this is one of the odd edge cases which give a need for simple attribute definitions.