ocfs2: remove unnecessary null pointer check before kmem_cache_destroy()

ocfs2: remove unnecessary null pointer check before kmem_cache_destroy()

As kmem_cache_destroy() already handles null pointers, so we can remove
the conditional test entirely.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Jun Piao <[email protected]>
Reviewed-by: Yiwen Jiang <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Joseph Qi <[email protected]>
Cc: Changwei Ge <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>