remove RecentBlocks from disk

app/scripts/metamask-controller.js

@@ -198,9 +198,7 @@ module.exports = class MetamaskController extends EventEmitter {
     this.networkController.store.subscribe((state) => {
       this.store.updateState({ NetworkController: state })
     })
-    this.recentBlocksController.store.subscribe((state) => {
-      this.store.updateState({ RecentBlocks: state })
-    })
+
     this.infuraController.store.subscribe((state) => {
       this.store.updateState({ InfuraController: state })
     })

app/scripts/migrations/021.js

@@ -28,6 +28,7 @@ module.exports = {
 function transformState (state) {
   const newState = state
   delete newState.BlacklistController
+  delete newState.RecentBlocks
   return newState
 }
 

test/unit/migrations/021-test.js

@@ -9,6 +9,7 @@ describe('wallet2 is migrated successfully with out the BlacklistController', ()
     .then((migratedData) => {
       assert.equal(migratedData.meta.version, 21)
       assert(!migratedData.data.BlacklistController)
+      assert(!migratedData.data.RecentBlocks)
       done()
     }).catch(done)
   })