Fix issue #6579824: Email crash observed after updating...

...device from JRN59D to JRN60

Deal correctly with multiprocess content providers that need to
be loaded into a secondary process; wasn't correctly detecting the
case where the IContentProvider returned by the activity manager
is null.  (installProvider used to be given the direct IContentProvider,
now it gets the ContentProviderHolder and much check whether the
provider inside is null.)

Change-Id: I888622e275a459031ab849952941f39cf9c02ee0

Author: Dianne Hackborn

core/java/android/app/ActivityThread.java

@@ -4516,7 +4516,7 @@ private IActivityManager.ContentProviderHolder installProvider(Context context,
             boolean noisy, boolean noReleaseNeeded, boolean stable) {
         ContentProvider localProvider = null;
         IContentProvider provider;
-        if (holder == null) {
+        if (holder == null || holder.provider == null) {
             if (DEBUG_PROVIDER || noisy) {
                 Slog.d(TAG, "Loading provider " + info.authority + ": "
                         + info.name);