Fix RoleService bug where response doesn't match struct

[hasan07]

Example raw response:

{"role":{"type":"DomainAdmin","id":"fake-id-12312312","name":"test-name","description":"test Role"}}

Struct doesn't match raw response, so the unmarshaller wasn't able to unmarshal properly and the response is always empty.

This fix handles the bug.

@mlsorensen FYI

[mlsorensen]

We will need to fix it in the code gen. I think this is another manifestation of #55 - anything that doesn't return a list type response seems to be broken. We will need to come up with a general solution @shwstppr @rohityadavcloud

[yadvr]

Agree, the changes should ideally be fixed in generator otherwise they maybe reverted the next time we update the code base against new listApis.

[mlsorensen]

Should be resolved with #58