branches/zip: Fix two bugs in the buddy allocator.

buf_buddy_block_free(): Remove the block from buf_pool->zip_hash.

buf_buddy_alloc_clean(): Test for buf_page_in_file() before
invoking buf_LRU_free_block().  The LRU list also contains "half-freed"
blocks (state == BUF_BLOCK_REMOVE_HASH).

buf/buf0buddy.c

@@ -87,6 +87,8 @@ buf_buddy_block_free(
 		    ((buf_block_t*) bpage)->frame == buf);
 	ut_a(bpage);
 	ut_a(buf_page_get_state(bpage) == BUF_BLOCK_MEMORY);
+	HASH_DELETE(buf_page_t, hash, buf_pool->zip_hash, fold, bpage);
+
 	ut_d(memset(buf, 0, UNIV_PAGE_SIZE));
 
 	block = (buf_block_t*) bpage;
@@ -215,6 +217,13 @@ buf_buddy_alloc_clean(
 		void*		ret;
 		mutex_t*	block_mutex = buf_page_get_mutex(bpage);
 
+		if (!buf_page_in_file(bpage)) {
+
+			/* This is most likely BUF_BLOCK_REMOVE_HASH,
+			that is, the block is already being freed. */
+			continue;
+		}
+
 		mutex_enter(block_mutex);
 
 		/* Keep the compressed pages of uncompressed blocks. */