Added a settings for CMAS message broadcast

This is for sl4a automation to receive CMAS messages
broadcasdt. The automation should inject the settings
through 'adb settings'.

Test: manual
bug: 34393649
Change-Id: Ic29be11b641f185219146d7fbb05561f5907ea76
diff --git a/core/tests/coretests/src/android/provider/SettingsBackupTest.java b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
index 76331a8..ae97ccd 100644
--- a/core/tests/coretests/src/android/provider/SettingsBackupTest.java
+++ b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
@@ -391,6 +391,7 @@
                  Settings.Secure.BACKUP_TRANSPORT,
                  Settings.Secure.BLUETOOTH_HCI_LOG,
                  Settings.Secure.CARRIER_APPS_HANDLED,
+                 Settings.Secure.CMAS_ADDITIONAL_BROADCAST_PKG,
                  Settings.Secure.COMPLETED_CATEGORY_PREFIX,
                  Settings.Secure.CONNECTIVITY_RELEASE_PENDING_INTENT_DELAY_MS,
                  Settings.Secure.DEFAULT_INPUT_METHOD,