ISPN-4860 Separate previous value reading for Hot Rod 1.x and 2.x

* Each major protocol version has different expectations on whether the previous value is present or not. The key difference, as indicated in the documentation, is that when no previous value is to be returned, not even the length is provided in 2.x. Before, in 1.x, the length was there regardless. 2.x enhances processing but using fully dedicated status codes for when the previous value is returned.
* Added further tests for Hot Rod 1.x protocol to make sure code remains backwards compatible.