Fix phone account settings translations

Use phone_accounts instead of phone_account_settings; the strings were
identical but for some reason we only had translations for the former.

Bug:18057447
Change-Id: I873c0677f94355f9f10c72e820a6c313e51d92cc
diff --git a/res/xml/phone_account_settings.xml b/res/xml/phone_account_settings.xml
index f812885..abb4995 100644
--- a/res/xml/phone_account_settings.xml
+++ b/res/xml/phone_account_settings.xml
@@ -16,7 +16,7 @@
 
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:phone="http://schemas.android.com/apk/res/com.android.phone"
-    android:title="@string/phone_account_settings">
+    android:title="@string/phone_accounts">
 
     <com.android.phone.settings.AccountSelectionPreference
         android:key="default_outgoing_account"