cros: Remove the disabled next button on offline gaia page

Bug: 789509
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I0f25e5f282508975ba2b969c1c1f7cf74fc51c30
Reviewed-on: https://chromium-review.googlesource.com/801118
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521062}

chrome/browser/resources/chromeos/login/offline_gaia.html

@@ -104,8 +104,6 @@
           </oobe-back-button>
           <div class="flex">
           </div>
-          <oobe-next-button inverse disabled>
-          </oobe-next-button>
         </div>
       </oobe-dialog>
     </template>