cleanup(di): fix dart analyzer errors

Closes #3962

modules/angular2/src/core/di/binding.ts

@@ -460,8 +460,6 @@ function _normalizeBindings(bindings: Array<Type | Binding | any[]>,
                             res: Map<number, _NormalizedBinding | _NormalizedBinding[]>):
     Map<number, _NormalizedBinding | _NormalizedBinding[]> {
   ListWrapper.forEach(bindings, (b) => {
-    var key, factory, normalized;
-
     if (b instanceof Type) {
       _normalizeBinding(bind(b).toClass(b), res);
 

modules/angular2/src/core/di/injector.ts

@@ -19,9 +19,7 @@ import {
 } from './exceptions';
 import {FunctionWrapper, Type, isPresent, isBlank, CONST_EXPR} from 'angular2/src/core/facade/lang';
 import {Key} from './key';
-import {resolveForwardRef} from './forward_ref';
 import {SelfMetadata, HostMetadata, SkipSelfMetadata} from './metadata';
-import {reflector} from 'angular2/src/core/reflection/reflection';
 
 
 // Threshold for the dynamic version

modules/angular2/src/forms/directives/ng_control_name.ts

@@ -2,7 +2,6 @@ import {CONST_EXPR} from 'angular2/src/core/facade/lang';
 import {EventEmitter, ObservableWrapper} from 'angular2/src/core/facade/async';
 import {StringMap} from 'angular2/src/core/facade/collection';
 
-import {QueryList} from 'angular2/core';
 import {Query, Directive, LifecycleEvent} from 'angular2/metadata';
 import {forwardRef, Host, SkipSelf, Binding, Inject, Optional} from 'angular2/di';
 
@@ -88,7 +87,6 @@ export class NgControlName extends NgControl {
   validators: Function[];
   _added = false;
 
-  // Scope the query once https://github.com/angular/angular/issues/2603 is fixed
   constructor(@Host() @SkipSelf() parent: ControlContainer,
               @Optional() @Inject(NG_VALIDATORS) validators: Function[]) {
     super();

modules/angular2/src/forms/directives/ng_form_control.ts

@@ -1,7 +1,6 @@
 import {CONST_EXPR} from 'angular2/src/core/facade/lang';
 import {EventEmitter, ObservableWrapper} from 'angular2/src/core/facade/async';
 
-import {QueryList} from 'angular2/core';
 import {Query, Directive, LifecycleEvent} from 'angular2/metadata';
 import {forwardRef, Binding, Inject, Optional} from 'angular2/di';
 

modules/angular2/src/forms/directives/ng_model.ts

@@ -1,7 +1,6 @@
 import {CONST_EXPR} from 'angular2/src/core/facade/lang';
 import {EventEmitter, ObservableWrapper} from 'angular2/src/core/facade/async';
 
-import {QueryList} from 'angular2/core';
 import {Query, Directive, LifecycleEvent} from 'angular2/metadata';
 import {forwardRef, Binding, Inject, Optional} from 'angular2/di';
 

modules/angular2/src/forms/validators.ts

@@ -5,7 +5,7 @@ import {OpaqueToken} from 'angular2/di';
 
 import * as modelModule from './model';
 
-export const NG_VALIDATORS = CONST_EXPR(new OpaqueToken("NgValidators"));
+export const NG_VALIDATORS: OpaqueToken = CONST_EXPR(new OpaqueToken("NgValidators"));
 
 /**
  * Provides a set of validators used by form controls.