Agent gives the wrong error response to a set-request for read-only OID

[thom-nic]

Tested against v3.26.1

I have an OID with MAX-ACCESS read-only. If make a set-request with a valid v1 or v2c private community string, the response is the noAccess error.

I believe a response to a v1 request should be the readOnly error (RFC 1157)

The response to a v2c request should be the notWritable

If I'm using a v3 request with valid read-write credentials I think the response should also be notWritable, but it is noAccess.