wallet: have proper rawResource default.

Author: nodech

lib/wallet/wallet.js

@@ -2660,7 +2660,10 @@ class Wallet extends EventEmitter {
     output.address = coin.address;
     output.value = ns.value;
 
-    if (rawResource && rawResource.length > rules.MAX_RESOURCE_SIZE) {
+    if (!rawResource)
+      rawResource = EMPTY;
+
+    if (rawResource.length > rules.MAX_RESOURCE_SIZE) {
         throw new Error(
           `Resource size (${rawResource.length}) exceeds maximum `+
           `(${rules.MAX_RESOURCE_SIZE}) for name: ${name}.`