Marking deprecated recommendation request code as @removed.

Test: adb shell am instrument -e class android.net.NetworkRecommendationProviderTest -w com.android.frameworks.coretests/android.support.test.runner.AndroidJUnitRunner
Test: Built & ran
Bug: 37357264
Change-Id: I6d55fbad87b11c99e7ddac07cfaa82efeee33187