LU-11668 debug: print object type in mdd_parent_fid

LU-11668 debug: print object type in mdd_parent_fid

mdd_parent_fid() get parent fid for directory, but racer shows
the passed in object is not directory, print its type to help
debug.

Test-Parameters: trivial
Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Signed-off-by: Peter Jones <pjones@whamcloud.com>
Change-Id: I4b3eedb159fc0efccc15e35cb59010fe02fa9e01
Reviewed-on: https://review.whamcloud.com/33700
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>