kernel - Check B_NOTMETA in buffer release code

kernel - Check B_NOTMETA in buffer release code

* When releasing the VM pages backing a buffer cache buffer if B_NOTMETA
  is set on the buffer attempt to move the pages to the VM page cache
  instead of leaving them on the active or inactive queue.

* This partially deals with the double data caching which occurs when
  HAMMER's double_buffer mode is enabled by shortening the life of
  the pages backing the secondary buffer(s).