Delete unused variable.

This is no longer required because the body reader methods have access
to the version via the codec state.

zebra-network/src/protocol/codec.rs

@@ -284,7 +284,6 @@ impl Decoder for Codec {
                 );
 
                 let body_reader = Cursor::new(&body);
-                let v = self.builder.version;
                 match &command {
                     b"version\0\0\0\0\0" => self.read_version(body_reader),
                     b"verack\0\0\0\0\0\0" => self.read_verack(body_reader),