LU-2158 fsfilt: Remove lvfs_common.c

LU-2158 fsfilt: Remove lvfs_common.c

This change removes the lvfs_common.c file, and moves it's only
remaining functionality directly into the obd_lfs_fid2dentry function.
This should have no functional impact, and is merely a code cleanup
exercise.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Change-Id: I5f8588a17f6e7659a7d33c2a5f79792826976de4
Reviewed-on: http://review.whamcloud.com/5193
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>