fix all apps button selector for launcher 3

Test: $ make ... AppSmoke
      install apk
      $ adb shell am instrument -w -r   -e debug false \
        -e log false -e timeout_msec 300000 \
        -e exclude_apps "'Google Now Launcher,Voice \
        Search,Google,Downloads,Device Policy'" \
        android.test.appsmoke/android.support.test.runner.AndroidJUnitRunner

Change-Id: Iea80289b10a37af12504fd2b6249351f84ebdda4