Fix unread messages timestamp comparison

Closes #6302
// FREEBIE

src/org/thoughtcrime/securesms/ConversationAdapter.java

@@ -289,7 +289,7 @@ public class ConversationAdapter <V extends View & BindableConversationItem>
       Cursor        cursor        = getCursorAtPositionOrThrow(i);
       MessageRecord messageRecord = getMessageRecord(cursor);
 
-      if (messageRecord.getTimestamp() < lastSeen) {
+      if (messageRecord.getDateReceived() <= lastSeen) {
         return i;
       }
     }
@@ -335,7 +335,7 @@ public class ConversationAdapter <V extends View & BindableConversationItem>
     return Util.hashCode(calendar.get(Calendar.YEAR), calendar.get(Calendar.DAY_OF_YEAR));
   }
 
-  public long getTimestamp(int position) {
+  public long getReceivedTimestamp(int position) {
     if (!isActiveCursor())          return 0;
     if (isHeaderPosition(position)) return 0;
     if (isFooterPosition(position)) return 0;
@@ -345,7 +345,7 @@ public class ConversationAdapter <V extends View & BindableConversationItem>
     Cursor        cursor        = getCursorAtPositionOrThrow(position);
     MessageRecord messageRecord = getMessageRecord(cursor);
 
-    return messageRecord.getTimestamp();
+    return messageRecord.getDateReceived();
   }
 
   @Override
@@ -388,8 +388,8 @@ public class ConversationAdapter <V extends View & BindableConversationItem>
         return false;
       }
 
-      long currentRecordTimestamp  = adapter.getTimestamp(position);
-      long previousRecordTimestamp = adapter.getTimestamp(position + 1);
+      long currentRecordTimestamp  = adapter.getReceivedTimestamp(position);
+      long previousRecordTimestamp = adapter.getReceivedTimestamp(position + 1);
 
       return currentRecordTimestamp > lastSeenTimestamp && previousRecordTimestamp < lastSeenTimestamp;
     }