[release-v2.0] jsonrpc: Let client handle empty VSP policy fields

Changing nil to empty map is handled in VSP client v4.0.1 so this
behaviour is no longer required in dcrwallet.

Backport of ce5dae7.

Author: jholdstock

go.mod

@@ -28,7 +28,7 @@ require (
 	github.com/decred/dcrd/wire v1.7.0
 	github.com/decred/go-socks v1.1.0
 	github.com/decred/slog v1.2.0
-	github.com/decred/vspd/client/v4 v4.0.0
+	github.com/decred/vspd/client/v4 v4.0.1
 	github.com/decred/vspd/types/v3 v3.0.0
 	github.com/gorilla/websocket v1.5.1
 	github.com/jessevdk/go-flags v1.5.0

go.sum

@@ -77,8 +77,8 @@ github.com/decred/go-socks v1.1.0 h1:dnENcc0KIqQo3HSXdgboXAHgqsCIutkqq6ntQjYtm2U
 github.com/decred/go-socks v1.1.0/go.mod h1:sDhHqkZH0X4JjSa02oYOGhcGHYp12FsY1jQ/meV8md0=
 github.com/decred/slog v1.2.0 h1:soHAxV52B54Di3WtKLfPum9OFfWqwtf/ygf9njdfnPM=
 github.com/decred/slog v1.2.0/go.mod h1:kVXlGnt6DHy2fV5OjSeuvCJ0OmlmTF6LFpEPMu/fOY0=
-github.com/decred/vspd/client/v4 v4.0.0 h1:8qFB3t5CyBFuUU0LarJFsq/+twfUMPALwzOsB99r818=
-github.com/decred/vspd/client/v4 v4.0.0/go.mod h1:jhqu4KGGOskQcPVZ3XZLVZ1Wgkc9GQo+oEipr3gGODg=
+github.com/decred/vspd/client/v4 v4.0.1 h1:eoFWCoaqEMLBODRQrVABGcpFrFdOSPLiMWpPO+RVvi0=
+github.com/decred/vspd/client/v4 v4.0.1/go.mod h1:jhqu4KGGOskQcPVZ3XZLVZ1Wgkc9GQo+oEipr3gGODg=
 github.com/decred/vspd/types/v3 v3.0.0 h1:jHlQIpp6aCjIcFs8WE3AaVCJe1kgepNTq+nkBKAyQxk=
 github.com/decred/vspd/types/v3 v3.0.0/go.mod h1:hwifRZu6tpkbhSg2jZCUwuPaO/oETgbSCWCYJd4XepY=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=

internal/rpc/jsonrpc/methods.go

@@ -4841,18 +4841,6 @@ func (s *Server) setVoteChoice(ctx context.Context, icmd any) (any, error) {
 func (s *Server) updateVSPVoteChoices(ctx context.Context, w *wallet.Wallet, ticketHash *chainhash.Hash,
 	choices map[string]string, tspendPolicy map[string]string, treasuryPolicy map[string]string) error {
 
-	// Ensure empty (as opposed to nil) choices on every category (required
-	// by the contract of the VSP API).
-	if choices == nil {
-		choices = map[string]string{}
-	}
-	if tspendPolicy == nil {
-		tspendPolicy = map[string]string{}
-	}
-	if treasuryPolicy == nil {
-		treasuryPolicy = map[string]string{}
-	}
-
 	if ticketHash != nil {
 		vspHost, err := w.VSPHostForTicket(ctx, ticketHash)
 		if err != nil {