Enable eslint file resolution linting (#2119)

Previously this was disabled (perhaps unintentionally due to the
duplicate settings in the .eslintrc.js). Enable the lint rule and fix
the violations.

May fix JS build issues on case-sensitive filesystems.

.eslintrc.js

@@ -28,13 +28,12 @@ module.exports = {
     'react/no-unused-prop-types': [1, { 'customValidators': [], skipShapeProps: true }],
     'no-param-reassign': 0,
     'new-cap': 0,
-    'import/no-unresolved': 'error',
+    'import/no-unresolved': 2,
     'linebreak-style': 0,
     'import/no-named-as-default': 'off',
     'import/no-named-as-default-member': 'off',
     'import/extensions': 0,
     'import/no-extraneous-dependencies': 0,
-    'import/no-unresolved': 0,
     'no-underscore-dangle': 0,
     'jsx-a11y/no-static-element-interactions': 'off'
   },

frontend/pages/admin/AppSettingsPage/AppSettingsPage.tests.jsx

@@ -1,7 +1,7 @@
 import expect, { restoreSpies } from 'expect';
 import { mount } from 'enzyme';
 
-import AppSettingsPage from 'pages/Admin/AppSettingsPage';
+import AppSettingsPage from 'pages/admin/AppSettingsPage';
 import { flatConfigStub } from 'test/stubs';
 import testHelpers from 'test/helpers';
 

frontend/pages/admin/UserManagementPage/UserManagementPage.tests.jsx

@@ -5,7 +5,7 @@ import { noop } from 'lodash';
 
 import * as authActions from 'redux/nodes/auth/actions';
 import { connectedComponent, reduxMockStore } from 'test/helpers';
-import ConnectedUserManagementPage, { UserManagementPage } from 'pages/Admin/UserManagementPage/UserManagementPage';
+import ConnectedUserManagementPage, { UserManagementPage } from 'pages/admin/UserManagementPage/UserManagementPage';
 import inviteActions from 'redux/nodes/entities/invites/actions';
 import userActions from 'redux/nodes/entities/users/actions';
 

frontend/router/index.jsx

@@ -3,8 +3,8 @@ import { browserHistory, IndexRedirect, IndexRoute, Route, Router } from 'react-
 import { Provider } from 'react-redux';
 import { syncHistoryWithStore } from 'react-router-redux';
 
-import AdminAppSettingsPage from 'pages/Admin/AppSettingsPage';
-import AdminUserManagementPage from 'pages/Admin/UserManagementPage';
+import AdminAppSettingsPage from 'pages/admin/AppSettingsPage';
+import AdminUserManagementPage from 'pages/admin/UserManagementPage';
 import AllPacksPage from 'pages/packs/AllPacksPage';
 import App from 'components/App';
 import AuthenticatedAdminRoutes from 'components/AuthenticatedAdminRoutes';