LU-1302 llog: pass lu_env to the llog callback

LU-1302 llog: pass lu_env to the llog callback

- Pass lu_env to he llog callback.
- Move cat_cancel_cb() to llog_cat.c to be with all
  other catalog functions.

Signed-off-by: Mikhail Pershin <tappro@whamcloud.com>
Change-Id: Iedbc7953b461ba52b52680d7d709d27c6581f934
Reviewed-on: http://review.whamcloud.com/3649
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>