Fix message receive timestamps on media messages.

app/src/main/java/org/thoughtcrime/securesms/database/MmsDatabase.java

@@ -940,7 +940,7 @@ public class MmsDatabase extends MessagingDatabase {
     contentValues.put(THREAD_ID, threadId);
     contentValues.put(CONTENT_LOCATION, contentLocation);
     contentValues.put(STATUS, Status.DOWNLOAD_INITIALIZED);
-    contentValues.put(DATE_RECEIVED, generatePduCompatTimestamp());
+    contentValues.put(DATE_RECEIVED, retrieved.isPushMessage() ? System.currentTimeMillis() : generatePduCompatTimestamp());
     contentValues.put(PART_COUNT, retrieved.getAttachments().size());
     contentValues.put(SUBSCRIPTION_ID, retrieved.getSubscriptionId());
     contentValues.put(EXPIRES_IN, retrieved.getExpiresIn());