Stop tracking old account balances after restore vault

Per @kgserrano note

app/scripts/metamask-controller.js

@@ -459,17 +459,30 @@ module.exports = class MetamaskController extends EventEmitter {
   //
 
   async createNewVaultAndKeychain (password, cb) {
+    this.forgetOldAccounts()
     const vault = await this.keyringController.createNewVaultAndKeychain(password)
     this.selectFirstIdentity(vault)
     return vault
   }
 
   async createNewVaultAndRestore (password, seed, cb) {
+    this.forgetOldAccounts()
     const vault = await this.keyringController.createNewVaultAndRestore(password, seed)
     this.selectFirstIdentity(vault)
     return vault
   }
 
+  forgetOldAccounts () {
+    const { accountTracker } = this
+    let oldAccounts = []
+    try {
+      oldAccounts = Object.keys(accountTracker.store.getState().accounts)
+    } catch (e) {
+      log.warn('Could not load old accounts to forget', e)
+    }
+    oldAccounts.forEach(addr => accountTracker.removeAccount(addr))
+  }
+
   selectFirstIdentity (vault) {
     const { identities } = vault
     const address = Object.keys(identities)[0]