fix: custom error handling for all wallets and cache update

lib/plugins/wallet/zcashd/zcashd.js

@@ -19,7 +19,7 @@ function rpcConfig () {
       port: config.rpcport || cryptoRec.defaultPort
     }
   } catch (err) {
-    throw err
+    throw new Error('wallet is currently not installed')
   }
 }