network.js: convert rpc protocol to lower case (#4855)

Fixes #4253

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Add Trezor Support
 - Allow to remove accounts (Imported and Hardware Wallets)
 - [#4840](https://github.com/MetaMask/metamask-extension/pull/4840): Now shows notifications when transactions are completed.
+- [#4855](https://github.com/MetaMask/metamask-extension/pull/4855): network.js: convert rpc protocol to lower case.
 
 ## 4.8.0 Thur Jun 14 2018
 

app/scripts/controllers/network/network.js

@@ -9,6 +9,7 @@ const extend = require('xtend')
 const EthQuery = require('eth-query')
 const createEventEmitterProxy = require('../../lib/events-proxy.js')
 const log = require('loglevel')
+const urlUtil = require('url')
 const {
   ROPSTEN,
   RINKEBY,
@@ -155,6 +156,8 @@ module.exports = class NetworkController extends EventEmitter {
   }
 
   _configureStandardProvider ({ rpcUrl }) {
+    // urlUtil handles malformed urls
+    rpcUrl = urlUtil.parse(rpcUrl).format()
     const providerParams = extend(this._baseProviderParams, {
       rpcUrl,
       engineParams: {