LU-4975 ldlm: fix comments for ldlm_glimpse_ast()

LU-4975 ldlm: fix comments for ldlm_glimpse_ast()

While reviewing comments on ofd_intent_policy() I realized that the
comment for ldlm_glimpse_ast() has become outdated.  The handling of
glimpse errors was moved to ldlm_handle_ast_error() back in commit
f10cebc5729 (b=23174).

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I369698b828d32fae899a10a0ede2b06b8ba6048b
Reviewed-on: http://review.whamcloud.com/11135
Tested-by: Jenkins
Reviewed-by: Ned Bass <bass6@llnl.gov>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>