LU-687 ldiskfs: resolve section dynlocks mismatch

LU-687 ldiskfs: resolve section dynlocks mismatch

Fix __init/__exit section mismatch.

  WARNING: lustre-2.1.0/ldiskfs/ldiskfs/ldiskfs.o(.init.text+0x1bc):
  Section mismatch in reference from the function init_module() to the
  function .exit.text:dynlock_cache_exit().  An __init init_module()
  function references a function __exit dynlock_cache_exit().

  This is often seen when error handling in the init function uses
  functionality in the exit path.  The fix is often to remove the
  __exit annotation of dynlock_cache_exit() so it may be used outside
  an exit section.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Ie0bdde7f78c18bca1127151175cf56bfa6ad500c
Reviewed-on: http://review.whamcloud.com/2019
Tested-by: Hudson
Reviewed-by: Jinshan Xiong <jinshan.xiong@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>