LU-5304: do not memset after LIBCFS_ALLOC

LU-5304: do not memset after LIBCFS_ALLOC

LIBCFS_ALLOC already zero out the memory allocated, so there is no
need to zero out the memory again.

Signed-off-by: Frank Zago <fzago@cray.com>
Change-Id: Iac0210eefa999e6ef52bb16cacc67854ef5a8cfa
Reviewed-on: http://review.whamcloud.com/11012
Reviewed-by: Patrick Farrell <paf@cray.com>
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>