Pass string key when updating ringtone.

Instead of passing in the preference.

Bug: 18232725
Change-Id: Ic0eec7cd62f1d9106da4de6d9aa29aeeead9cc0e
diff --git a/src/com/android/dialer/settings/GeneralSettingsFragment.java b/src/com/android/dialer/settings/GeneralSettingsFragment.java
index d04fae3..578ff33 100644
--- a/src/com/android/dialer/settings/GeneralSettingsFragment.java
+++ b/src/com/android/dialer/settings/GeneralSettingsFragment.java
@@ -107,7 +107,7 @@
                             mContext,
                             mRingtoneLookupComplete,
                             RingtoneManager.TYPE_RINGTONE,
-                            mRingtonePreference,
+                            mRingtonePreference.getKey(),
                             MSG_UPDATE_RINGTONE_SUMMARY);
                 }
             }