LU-2158 lvfs: move ldiskfs only functions to osd-ldiskfs

LU-2158 lvfs: move ldiskfs only functions to osd-ldiskfs

Currently a lot of functions exist in the lvfs layer
that really belongs to different parts of the stack.
This patch moves osd-ldiskfs specific code that
is located in the lvfs layer into the proper
location.

Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: Ia197391599cc7fffad396d487873edd9d6c0b1c4
Reviewed-on: http://review.whamcloud.com/5246
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>