Fix a typo in WSDL#findChildParameterObject

[arthurschreiber]

I'm not quite sure what impact this typo had, but it's obviously wrong.

I stumbled over this when reviewing the code changes between 0.6.0 and 0.6.1.

[herom]

Thanks a lot @arthurschreiber - this seems like it was really borked... it seems that we didn't really have a test for this scenario, as it's obviously wrong 😨

Because, if you try it in your console, you can see that:

var x = [1, 2, 3];
var isBorked =Array.isArray(x && x.length); // returns `false` because `x && x.length === 3` (!)

console.log('Check for `isArray` on `x`: ' + isBorked; // returns false