Explicitly export content providers

In a future version of Android, the default value for
<provider android:exported> will change from true to false.
Explicitly set android:exported="true"

Bug: 3306452
Change-Id: Ib55397f4f582bab66123f358523d117bd6e0b7cc
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 5a98579..feefaaf 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -20,6 +20,7 @@
                  android:label="@string/app_label">
 
         <provider android:name=".DrmProvider" android:authorities="drm"
+                android:exported="true"
                 android:multiprocess="false" />
 
         <receiver android:name=".DrmPushReceiver"