Contacts provider needs to be a privileged apk

Also fixes a sometimes-bug: the contacts database helper can be
invoked for upgrade prior to system boot, but it sends broadcasts.
Use FLAG_RECEIVER_REGISETRED_ONLY_BEFORE_BOOT flag to avoid problems.

Bug 8765951

Change-Id: I4ee4b4c3e17803e73c63e7a2e06e35088d1a611d
diff --git a/Android.mk b/Android.mk
index df4d245..1698686 100644
--- a/Android.mk
+++ b/Android.mk
@@ -28,6 +28,7 @@
 
 LOCAL_PACKAGE_NAME := ContactsProvider
 LOCAL_CERTIFICATE := shared
+LOCAL_PRIVILEGED_MODULE := true
 
 LOCAL_PROGUARD_FLAG_FILES := proguard.flags