stop exporting EmailAccountCacheProvider

Bug: 29767043
Change-Id: Ib9f16385a5e63557b6f293d148e49c9ad044c9b4
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index c3e33ab..bbe02d4 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -393,7 +393,7 @@
         <provider
             android:authorities="com.android.email.accountcache"
             android:label="@string/account_cache_provider"
-            android:exported="true"
+            android:exported="false"
             android:name="com.android.mail.providers.EmailAccountCacheProvider" >
             <grant-uri-permission android:pathPattern=".*" />
         </provider>