Relax protected broadcast check to allow shell.

The shell is often used for developer testing, so we shouldn't
require all of its broadcasts to be protected.

Bug: 27273532
Change-Id: Ic6f262dd11223dee5655614aad30365d51e180c5

services/core/java/com/android/server/am/ActivityManagerService.java

@@ -16960,7 +16960,6 @@ public final class ActivityManagerService extends ActivityManagerNative
             case Process.ROOT_UID:
             case Process.SYSTEM_UID:
             case Process.PHONE_UID:
-            case Process.SHELL_UID:
             case Process.BLUETOOTH_UID:
             case Process.NFC_UID:
                 isCallerSystem = true;