rpc: convert unknown procedures to VIR_ERR_NO_SUPPORT

rpc: convert unknown procedures to VIR_ERR_NO_SUPPORT

Libvirt special-cases a specific VIR_ERR_RPC from the remote driver
back into VIR_ERR_NO_SUPPORT on the client, so that clients can
handle missing rpc functions the same whether the hypervisor driver
is local or remote.  However, commit c1b22644 introduced a regression:
VIR_FROM_THIS changed from VIR_FROM_REMOTE to VIR_FROM_RPC, so the
special casing no longer works if the server uses the newer error
domain.

* src/rpc/virnetclientprogram.c
(virNetClientProgramDispatchError): Also cater to 0.9.3 and newer.