[FIX] on connect return error if server doesn't have validated ledgers

test/fixtures/rippled/empty.json

@@ -0,0 +1,7 @@
+{
+  "id": 0,
+  "status": "success",
+  "type": "response",
+  "result": {
+  }
+}

test/fixtures/rippled/index.js

@@ -1,4 +1,4 @@
-'use strict';
+'use strict'; // eslint-disable-line 
 
 module.exports = {
   submit: {
@@ -12,6 +12,7 @@ module.exports = {
     withSettingsTx: require('./ledger-with-settings-tx'),
     withStateAsHashes: require('./ledger-with-state-as-hashes')
   },
+  empty: require('./empty'),
   subscribe: require('./subscribe'),
   unsubscribe: require('./unsubscribe'),
   account_info: {
@@ -31,6 +32,7 @@ module.exports = {
   },
   server_info: {
     normal: require('./server-info'),
+    noValidated: require('./server-info-no-validated'),
     error: require('./server-info-error')
   },
   path_find: {

test/fixtures/rippled/server-info-no-validated.json

@@ -0,0 +1,31 @@
+{
+  "id": 0,
+  "status": "success",
+  "type": "response",
+  "result": {
+    "info": {
+      "build_version": "0.30.1-hf2",
+      "complete_ledgers": "empty",
+      "hostid": "ARTS",
+      "io_latency_ms": 1,
+      "last_close": {
+        "converge_time_s": 2.007,
+        "proposers": 4
+      },
+      "load_factor": 1,
+      "peers": 53,
+      "pubkey_node": "n94wWvFUmaKGYrKUGgpv1DyYgDeXRGdACkNQaSe7zJiy5Znio7UC",
+      "server_state": "connected",
+      "network_ledger" : "waiting",
+      "closed_ledger": {
+        "age": 5,
+        "base_fee_xrp": 0.00001,
+        "hash": "4482DEE5362332F54A4036ED57EE1767C9F33CF7CE5A6670355C16CECE381D46",
+        "reserve_base_xrp": 20,
+        "reserve_inc_xrp": 5,
+        "seq": 6595042
+      },
+      "validation_quorum": 3
+    }
+  }
+}