branches/zip: buf_page_get_gen(): Obey recv_no_ibuf_operations

and do not call ibuf_merge_or_delete_for_page() in crash recovery,
before the redo log has been applied.
This could cure some hard-to-repeat, hard-to-explain bugs
related to secondary indexes.

A possible recipe to repeat the bug:

1. update a secondary index leaf page on a compressed table
2. evict the page from the buffer pool while it is still dirty
3. ibuf_insert() something for the page
4. crash
5. crash recovery; ibuf merge would be done too early,
before applying redo log to the sec index page or the ibuf pages

ChangeLog

+2010-01-21	The InnoDB Team
+
+	* buf/buf0buf.c:
+	Do not merge buffered inserts to compressed pages before
+	the redo log has been applied in crash recovery.
+
 2010-01-13	The InnoDB Team
 
 	* row/row0sel.c:

buf/buf0buf.c

@@ -2239,7 +2239,7 @@ wait_until_unfixed:
 		while not holding buf_pool_mutex or block->mutex. */
 		success = buf_zip_decompress(block, srv_use_checksums);
 
-		if (UNIV_LIKELY(success)) {
+		if (UNIV_LIKELY(success && !recv_no_ibuf_operations)) {
 			ibuf_merge_or_delete_for_page(block, space, offset,
 						      zip_size, TRUE);
 		}