Don't set mLockscreenWallpaper when wallpaper is not supported.

Bug: 138939803
Bug: 144862300

Test: a CtsAppTestCases:android.app.cts.WallpaperManagerTest

Merged-In: Ibb5dd6097939a5b50244ee3cec5ee09a1f5417cb
Change-Id: Ibb5dd6097939a5b50244ee3cec5ee09a1f5417cb
(cherry picked from commit e8d7b883b4e30572cd1d6d9655394ef05be93621)
1 file changed