Problem:
=======
  While evicting the uncompressed page from buffer pool, InnoDB writes
the checksum for the compressed page in buf_LRU_free_page().
So while flushing the compressed page, checksum validation fails
when innodb_checksum_algorithm variable changed to strict_none.

Solution:
========
- Calculate the checksum only during flushing of page. Removed the
checksum write in buf_LRU_free_page().