Fix updating of pending transactions

Transaction statuses were not being properly updated when:

- MetaMask was unlocked
- The network was changed

This PR fixes both of those. Fixes #5174

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Current Develop Branch
 
+- Update transaction statuses when switching networks.
+
 ## 4.12.0 Thursday September 27 2018
 
 - Reintroduces changes from 4.10.0

app/scripts/controllers/transactions/index.js

@@ -530,6 +530,7 @@ class TransactionController extends EventEmitter {
     Updates the memStore in transaction controller
   */
   _updateMemstore () {
+    this.pendingTxTracker.updatePendingTxs()
     const unapprovedTxs = this.txStateManager.getUnapprovedTxList()
     const selectedAddressTxList = this.txStateManager.getFilteredTxList({
       from: this.getSelectedAddress(),

app/scripts/metamask-controller.js

@@ -555,6 +555,7 @@ module.exports = class MetamaskController extends EventEmitter {
     }
 
     await this.preferencesController.syncAddresses(accounts)
+    await this.txController.pendingTxTracker.updatePendingTxs()
     return this.keyringController.fullUpdate()
   }