Do not export RcsProvider

Access to the RcsProvider should be restricted to the user
android.uid.phone, which TelephonyProvider already uses.

Test: CtsRcsTestCases
Change-Id: Icd990aaebf4c0adbddf9f29a107018189b7d6433
Bug: 124000636
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 2e61ef9..4ae9acf 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -123,7 +123,7 @@
         <provider android:name="RcsProvider"
                   android:authorities="rcs"
                   android:multiprocess="false"
-                  android:exported="true"
+                  android:exported="false"
                   android:singleUser="true" />
 
         <service