Fix issue #418 for DeleteAsync

[james-hester]

No description provided.

[mgravell]

I'm confused because the linked bug reports to be fixed; do you have an example (ideally as a test) that shows this problem happening, and then not happening with the fix?

[james-hester]

Sorry for the confusion. The test case in the last commit illustrates the problem. Without the fix, it throws the following exception:

System.Data.DataException: GetAsync<T> only supports an entity with a single [Key] or [ExplicitKey] property. [Key] Count: 1, [ExplicitKey] Count: 1

[NickCraver]

@mgravell for context: this was fixed in the sync version, but not the async version - I agree let's make them match here, but then we'll need to rewrite all this stuff when time ever allows - it's far from optimal (and maintainable) at the moment but that's because it hasn't been extremely coordinated.