LU-4008 mdt: Shrink default LOVEA reply buffers

LU-4008 mdt: Shrink default LOVEA reply buffers

Instead of allocating maximum possible LOVEA for intent requests,
allocate a sane default to fit up to 100 stripes, should the size
be bigger, the buffer reallocation code will kick in.

Additionally, since quite awhile ago we no longer send
unlink cookies or EA data to the clients from unlinks/renames,
so we no longer need to allocate reply buffer for them in
mdt_close() and other such places.
Also clean up unused fields related to these buffers in
md_attr structure.

Lustre-commit: 00260466f9c84f21e6db55d5dd6e87e8a9906438
Lustre-change: http://review.whamcloud.com/9322

Change-Id: I06b9f5665ec2616cd9a5d483872369d710400d22
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Reviewed-on: http://review.whamcloud.com/9942
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>