BUG#16069598 - SERVER CRASH BY NULL POINTER DEREFERENCING IN

               MEM_HEAP_CREATE_BLOCK() 

PROBLEM
-------

If we give start mysqld with the option --innodb_log_buffer_size=50GB
,then  mem_area_alloc() function fails to allocate memory and returns
NULL.In debug version we assert at this point,but there is no check in
release version and we get a segmentation fault.

FIX
---
Added a log message saying that we are unable to allocate memory.
After this message we assert.

[Approved by Kevin http://rb.no.oracle.com/rb/r/2065 ]

storage/innobase/mem/mem0mem.c

@@ -353,7 +353,13 @@ mem_heap_create_block(
 		block = (mem_block_t*) buf_block->frame;
 	}
 
-	ut_ad(block);
+	if(!block) {
+		ut_print_timestamp(stderr);
+		fprintf(stderr,
+			" InnoDB: Unable to allocate memory of size %lu.\n",
+			len);
+		ut_error;
+	}
 	block->buf_block = buf_block;
 	block->free_block = NULL;
 #else /* !UNIV_HOTBACKUP */