ref: Setup messages should always be exchanged by VIFs and should be async.

This change also removes support for RPCVersion5.

MultiPart: 2/2
Change-Id: Ie8d3cb30170ca8fac58594197ad0f28108957e3c
diff --git a/profiles/internal/rpc/stream/vc/auth.go b/profiles/internal/rpc/stream/vc/auth.go
index b74a351..e19d10f 100644
--- a/profiles/internal/rpc/stream/vc/auth.go
+++ b/profiles/internal/rpc/stream/vc/auth.go
@@ -110,10 +110,8 @@
 	if err := enc.Encode(b); err != nil {
 		return verror.New(stream.ErrNetwork, nil, verror.New(errVomEncodeBlessing, nil, err))
 	}
-	if v >= version.RPCVersion5 {
-		if err := enc.Encode(discharges); err != nil {
-			return verror.New(stream.ErrNetwork, nil, verror.New(errVomEncodeBlessing, nil, err))
-		}
+	if err := enc.Encode(discharges); err != nil {
+		return verror.New(stream.ErrNetwork, nil, verror.New(errVomEncodeBlessing, nil, err))
 	}
 	msg, err := crypter.Encrypt(iobuf.NewSlice(buf.Bytes()))
 	if err != nil {
@@ -161,10 +159,8 @@
 		return noBlessings, nil, verror.New(stream.ErrNetwork, nil, err)
 	}
 	var discharges []security.Discharge
-	if v >= version.RPCVersion5 {
-		if err := dec.Decode(&discharges); err != nil {
-			return noBlessings, nil, verror.New(stream.ErrNetwork, nil, err)
-		}
+	if err := dec.Decode(&discharges); err != nil {
+		return noBlessings, nil, verror.New(stream.ErrNetwork, nil, err)
 	}
 	if !sig.Verify(blessings.PublicKey(), append(tag, crypter.ChannelBinding()...)) {
 		return noBlessings, nil, verror.New(stream.ErrSecurity, nil, verror.New(errInvalidSignatureInMessage, nil))